Influenza

During the spring of 1918 extensive epidemics of influenza occurred in England, on the continent of Europe, and in various parts of the United States. At that time the disease was more or less mild in character and there were not enough fatalities to excite real apprehension. Indeed, no indication was given of the unprecedented and frightfully fatal epidemics which were to sweep over the entire world in the autumn when the pandemic culminated.

In retrospect it thus appears that two separate series of influenza epidemics occurred during the year. The belief that it was the same disease in each instance is supported by the fact that many men of the Navy who had influenza in the spring or summer of 1918, while in European waters, escaped during the later epidemics both in Europe and in the United States. The British Grand Fleet experienced the same thing; with few exceptions those men who contracted influenza in May and June were not attacked during the more fatal epidemics in October, November, and December. The conclusion is that mild attacks earlier in the year, as a rule, conferred immunity against the more fatal type of the disease which prevailed subsequently.

In fact, there is good ground for the view that many at least of the sporadic cases diagnosed as grippe during interpandemic years are really influenza and that this disease is quite as much an entity as measles and other well-recognized communicable diseases. This

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Chart No. 4

Annual admission rates per 1,000, by weeks, for communicable diseases, exclusive of influenza and the venereal diseases, at shore stations and for the entire Navy, fiscal year ended June 30, 1918.


is perhaps worth mentioning in passing because of the conflict of opinion which has arisen during the past year.

Pandemics of influenza have been occurring periodically for centuries. If the 1918 pandemic is a criterion, they do not appear suddenly but develop gradually, the incidence and prevalence of influenza, either in recognizable form or under diagnosis of various respiratory diseases, increasing for a year or two in many countries to such an extent as to be revealed plainly in annual mortality statistics. Presently, widespread fleeting epidemics of short duration, associated with low case-fatality rates, perhaps, and as a rule bearing little obvious relation to one another at the time, occur in many countries several months previous to the appearance of the disease in the type where starting in some part of the world one epidemic after another, each manifestly related to the one in the country or State just previously visited, spread progressively much after the fashion of prairie fires, over the entire inhabited portions of the globe, but few communities here and there escaping. The rate of spread during the autumn months of 1918 was so rapid indeed as to revive the old discussion as to the possibility of air-borne infection, but a review of the pandemic to date leads to a conviction that the disease can not spread faster than human beings travel.

Previous Pandemics of Influenza.

It is interesting to study the mortality rates for England and Wales where vital statistics are and for ages have been collected and compiled less imperfectly than in other countries. Because of the completeness and accuracy with which deaths have been recorded in parish registers it is possible to obtain mortality statistics of considerable value as far back as the sixteenth century and quite reliable figures from early in the eighteenth century. Dr. Otto R. Eichel, director of the division of vital statistics, New York State Department of Health, has recently made a study of the influenza mortality of England and Wales from the year 1510, and has plotted this, year by year, in terms of estimated influenza death-rate per million living per annum, except from 1838 forward, for which period exact rates are available. These data show the great pandemics as having occurred in England at intervals varying from 25 to 175 years apart, with the mortality from influenza remaining high for a period of years following each great outbreak and showing a general downward trend to a very low point preceding the next successive great epidemic.

The ordinates, which represent the annual exact or estimated rates, if smoothed by either free-hand drawing or by the procedure of "moving averages," would apparently result in great interpandemic curves of the hyperbolic or parabolic types. From these figures and curves one may infer that a great pandemic of influenza does not occur in a single great wave, covering a course of a few weeks or months and then disappearing, but that the disease, as reflected by the death rates, prevails extensively through a term of years within which there occur two or more years of very high death rates from this cause, or distinct epidemics of the disease.

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The history of influenza records a severe epidemic in 1510, another in 1557-58, again in 1657-58, and in 1729. Severe epidemics apparently occurred in four different years between 1729 and 1743, inclusive--1729, 1733, 1737, and 1743. Another severe epidemic occurred in 1833 and the disease continued in unusual prevalence through 1848. High death rates were again recorded in four different years--1833, 1837, 1847, and 1848-49. The next period of high death rates, during which the pandemic of 1889-90 occurred, lasted until 1900 and included high mortality rates from influenza in practically every year of the period, but particularly in 1891, 1892, 1893, 1895, 1898, 1899, and 1900.

From a summary of the course of events presented by Sir Arthur Newsholme it appears that no epidemic occurred in 1901. In 1902 a small epidemic lasting from six to eight weeks occurred. There were no epidemics in 1903, 1904, or 1905. An epidemic of low magnitude and somewhat protracted duration occurred in December, 1906, and in January, 1907. In 1908 a smarter epidemic occurred, culminating in the ninth week of the year. A similar epidemic occurred in 1909, reaching its maximum in the twelfth week of the year. No epidemics occurred in 1910, 1911, or 1912. In 1913 an epidemic of low range occurred with maximum mortality in the twelfth week of the year. No epidemic occurred in 1914. In 1915 an epidemic similar to that of 1913 reached its height late in February. A considerable low-ranged increase of mortality was visible in the early part of 1916, followed by a relatively small epidemic, culminating in the last week of the year and terminating early in 1917.

The last great period of influenza began, perhaps, in 1916 and culminated in the pandemic of 1918. The great epidemics in England and Wales came approximately with periods of widespread diffusion of the disease throughout all Europe in the early centuries and throughout the whole Eastern Hemisphere, and, indeed, the whole world, ini the later centuries, the great epidemics, probably, all indicating pandemics.

Mortality statistics of the United States furnish but little evidence relating to the 1847-48 pandemic and even those covering the 1889-90 pandemic are so lacking in completeness for practically all States that satisfactory comparison can not be made with the statistics of 1918-19. Morbidity statistics relating to the civil population, other than fragmentary clinical records, are unobtainable.

Analysis of reports from ships and stations of the Navy during 1889 and 1890 show that from 20 to 75 per cent of the various complements were attacked. While most of the reports speak of the disease as mild, certain of them mention complicating pneumonia and nephritis, and the disease at the naval station, San Francisco, seems to have been associated with a case fatality rate of 4 per cent, all the deaths being caused by pneumonia.

It is significant that the annual death rate per thousand for disease in the Navy in 1889 was 10.7. In 1887 it was 7.6 and in 1888, 9.2. Since 1889 the rate has not reached that figure until the present pandemic.

The annual death rate per 100,000 for pneumonia is also very significant. This rate in 1887 was 62.38; 1888, 70.31; and in 1889,

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Chart No. 5

Annual admission rates per 1,000, by weeks, for certain communicable diseases, at shore stations in the United States, calendar year 1918.


178.26; 1890, 169.95, and thereafter it did not again reach 100 until 1917, when it was 102.20.

Influenza in the Navy, 1889-90.

Influenza was not prevalent in the Navy in 1888.

The following summary of the influenza during the years 1889-90 is taken from the annual report of the Surgeon General of the Navy for the year 1890:

REPORT OF INFLUENZA

Prepared by Passed Assistant Surgeon Frank Anderson, United States Navy.

In response to the circular issued by the Bureau of Medicine and Surgery, requesting information relative to the recent influenza pandemic, replies have been received from 41 medical officers stationed as follows:

European Squadron 4
Atlantic coast of North America 23
Gulf coast of North America 1
Vessels cruising in the West Indies 3
Atlantic coast of South America 1
Pacific coast of North America 7
Hawaiian Islands 1
China 1

These reports embrace a period extending from the first appearance of the disease in December, 1889, to April 10, 1890, and will be considered in the order indicated above.

EUROPEAN SQUADRON.

The Chicago, Boston, and Atlanta arrived at Lisbon, Portugal, on December 21, 1889, the Yorktown on the 23rd.

Influenza had already been epidemic at this port for some weeks; more than 600 cases had been reported, and the number was daily increasing. The first case observed in the fleet occurred on the Chicago on December 23, two days after arrival, in an officer who had been on shore 36 hours previous to being attacked. Other cases followed each day in persons who had been on shore from 24 to 36 hours previous to being taken sick, and it was not until December 30 that a case occurred in a man who had not been out of the ship. The disease made its first appearance on the Boston and Yorktown on December 28, but did not break out upon the Atlanta until December 30, nine days after arrival. In regard to these last three vessels the reports do not state whether the first cases occurring on board were in persons who had been on shore, as was the case on the Chicago.

The following table shows the number of men on each ship, the dates of appearance of first and last cases, the time when the epidemic reached its maximum, the duration of the epidemic on board, and the percentage of persons attacked:

Name of vessel. Complement First
case.
Height of
epidemic.
Last
case.
Duration of
epidemic.
Per cent
attacked.
          Days  
Chicago 470 Dec. 23 Jan. 2 Jan. 21 29 60.0
Boston 315 Dec. 28 Jan. 2 Jan. 27 30 27.0
Atlanta 315 Dec. 30 Jan. 7 Jan. 24 25 27.0
Yorktown 190 Dec. 28 Jan. 3 Jan. 9 12 26.1

The crews of these vessels are composed chiefly of young and middle-aged men, and there is nothing to report as to a particular susceptibility manifested at any one period of life. All were subjected to much the same influences; and officers, sailors, marines, and engineers' force all suffered from the disease, with a somewhat smaller percentage of cases perhaps among the firemen and coal heavers.

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The following symptoms are recorded as prominent in the cases that occurred on these vessels: (a) Of the nervous system. Mental depression, melancholia, utter prostration, and wakefulness. Frontal headache, pain in the orbital regions, back, and limbs. Vertigo and tendency to syncope were experienced in some cases.

(b) Of the respiratory and circulatory organs. Fever preceded by chill. Temperature, 100.5°-104°. Catarrhal inflammation of respiratory passages in nearly every case. Difficulty in taking deep inspiration. Suffocative feeling. Little or no expectoration. Irregularity of heart beat in one case. Pulse ranging from 105 to 115 (in some cases it reached 120) slowly subsiding to normal and remaining weak for some days.

(c) Of the digestive organs. Loss of appetite, furred tongue, foul breath, nausea, occasionally vomiting during the chill. At times diarrhea. The derangement of digestion generally continued several days and was not readily amenable to treatment.

(d) Of the skin. Skin generally moist, often profuse perspiration. No eruptions were observed other than herpes labialis in two cases.

The following complications were observed: Pneumonia, pleuritis, and acute rheumatism. Empyema, phlebitis, persistent diarrhea occurred as sequelae in rare instances; but marked debility and bronchial catarrh commonly followed an attack.

Pneumonia occurred in five cases (one lobar) one of them proving fatal. There were 21 cases of relapse of the disease, as follows: Chicago, 13; Boston, 5; Atlanta, 3; Yorktown, 2.

Patients recovered quickly as a rule. The acute symptoms passed off rapidly, but patients were apt to remain debilitated for some time. Nine days was the longest time that a man remained on the sick list and one day the shortest, the average time upon the list being 2.8 days. There were of course many cases so mild that the patient did not go upon the list at all. The above figures refer to those who were sick enough to be excused from duty.

The disease did not have a marked influence upon other cases of sickness except in a case of emphysema and chronic bronchitis, in which a fatal termination was brought about.

Out f 486 cases of influenza occurring in the fleet there was but one death, a mortality of about one-fifth of 1 per cent. In this instance croupous pneumonia, involving the entire left lobe, was the cause of death.

Treatment.--Antipyrine and quinine were administered when a sedative action was desired. Salicylate of soda was given with marked benefit when rheumatism existed. Stimulants were administered only in complicated cases or where there was unusual debility.

It is the opinion of one medical officer only that the disease was positively contagious. One considers it probably so. Another believes it to be not contagious. The opinion of the fourth medical officer on this question is not expressed.

ATLANTIC COAST OF NORTH AMERICA.

From the Atlantic coast of North America reports were received as follows: The table gives the localities taken in order from north to south, and shows the dates of first and last cases observed, and the time when the disease seemed to have reached the maximum of intensity; also the duration of the epidemic in each place.

Locality. First
case.
Maximum. Last
case.
Duration
of epidemic.
        Days.
Portsmouth, N.H. Dec. 20 Jan. 15 Feb. 15 57
Boston Dec. 21 Jan. 15 Feb. 27 68
Newport Dec. 19 Jan. 15 Feb. 7 40
New York Dec. 16 Jan. 1 Jan. 26 41
Philadelphia Dec. 16 Jan. 5 Jan. 28 53
Annapolis Dec. 25 Jan. 7 Jan. 21 27
Washington Dec. 27 Jan. 13 Feb. 14 49
Richmond, Va. Dec. 11 ------ Feb. 12 32
Norfolk, Va. Dec. 26 Jan. 15 Feb. 28 64

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These reports are from various medical officers stationed at the above places and on different duty, some referring to navy yards and receiving or training ships and some to hospitals. The earliest and latest cases reported are taken as showing the extreme range of the epidemic at each locality.

The estimates as to the percentage of population attacked necessarily vary widely and can only be approximate, as the observations in some cases apply to only a small number of persons in a ship or barracks and in others to the population in the neighborhood of the station.

In Portsmouth, N.H., 32 per cent of the persons connected with the naval station were attacked. This includes women and children.

In Boston 8 per cent of those living on the receiving ship and 25 per cent of those living on shore and connected with the station suffered from the disease.

At Newport 21 per cent of the boys upon the training ship and 20 per cent of the population of the town, including both sexes and all ages, were attacked.

In New York 8 per cent of the complement of the training ship and 20 per cent of the marine garrison and officers of the yard, including families, were taken sick.

In Philadelphia 331/3 per cent is about the average of the various estimates formed. This applies to all ages and sexes.

At Annapolis, out of 450 officers, cadets, and enlisted men, 56 per cent were attacked. The percentage of sickness among the cadets alone was 75.

At Washington 20 per cent of the marine garrison were attacked, but taking into consideration all persons living in or around or employed in the navy yard, it is estimated that 70 per cent suffered from influenza.

At Richmond, Va., the disease did not become epidemic upon the vessels stationed there, but a few mild cases occurred.

At Norfolk, Va., from 20 per cent to 25 per cent of all ages and sexes were attacked. On the receiving ship 75 per cent of the ship's company were taken sick.

The majority of these observations apply to men in early adult or middle life, and therefore do not justify conclusions as to a greater susceptibility at any particular period of life or on the part of one sex more than the other. But at the Naval Academy 75 per cent of the cadets were attacked, while at the home for aged sailors at Philadelphia only 2 cases are recorded among the 196 inmates, which tends to show that early life suffered more than old age.

In the above series of observations the following symptoms are recorded as prominent:

(a) Of the nervous system.--Chill followed by fever; the temperature rarely rising above 103°. Insomnia and mental depression, in one case stupor lasting three days. Cephalgia, neuralgia of the great nerve trunks, pain in bones and muscles. In exceptional cases, spinal hyperaesthesia on pressure, a peculiar sinking lassitude indicative of collapse centered in the great nervous plexuses surrounding heart and stomach.

(b) Of the respiratory and circulatory organs.--Nasal catarrh, with photophobia, epistaxis, bronchitis, diminished heart power, rapid respiration, and weak pulse.

(c) Of the digestive organs.--Furred tongue, anorexia, vomiting, constipation, usually in commencement of disease, sometimes sudden diarrhea and evidence of catarrhal disturbance of gastro-intestinal canal (so-called abdominal cases).

(d) Of the skin.--Hyperaesthesia. General flushing of the skin, followed in some cases by a papular or pustular eruption. Urticaria. Sometimes the skin was unusually dry; sometimes there was sweating. Glandular swellings about the neck in a few cases.

Among the complications of the disease as it appeared on this coast are recorded bronchitis, neuralgia, rheumatism, pneumonia, nephritis, and conjunctivitis. At the Naval Academy several cases of otitis media followed the disease. In one instance pericarditis and in one, severe facial neuralgia. In two cases albuminuria is reported as continuing after the influenza disappeared.

Not many cases of pneumonia are reported. From Boston two cases of catarrhal pneumonia are reported. In Newport pneumonia is reported to have occurred in 3 per cent of the cases. In New York three cases of lobar, in Philadelphia two cases of lobar, and in Annapolis two cases of lobar pneumonia occurred. In Washington there were three cases of catarrhal pneumonia and in Norfolk one case.

In New York relapse is reported in 4 per cent of the cases in Newport in less than 1 per cent. From Boston there are reported two cases of relapse;

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from Portsmouth 3, Philadelphia, 2, Washington 3, Norfolk 6. At Annapolis there were no relapses.

Convalescence was varied, as follows: Portsmouth, protracted; Boston, slow, with tendency to relapse on exposure to bad weather; Newport, rapid in men and children, slow in women; New York, rapid in the training ship, in other instances tardy, with listlessness, debility, and harassing cough; Philadelphia, acute symptoms passed off rapidly, but debility continued. When throat was involved it was slow. Annapolis, slow; patients long debilitated; Washington, all cases slow and tedious; Richmond, rapid; Norfolk, rapid in uncomplicated cases, slow in others.

The influence of the disease upon other diseases was, as a rule, unfavorable and tended to aggravate them. It increased the liability to attacks and dminished the power to resist. It was observed to render cases of gonorrhea peculiarly obstinate. Death is reported to have been accelerated in phthisis and in a case of hydronephrosis.

Only one death is reported from any of the naval stations along this coast. This occurred at Boston and is attributed to cerebral congestion.

Treatment.--Antipyrine and antifebrin were administered when there was not excessive depression and usually relieved pain. Salicylates were employed when rheumatism existed as a complication, and proved satisfactory. Quinine and whisky, were administered when there was much depression. One oifficer employed only rest in bed with occasional warm baths and little or no medication. This treatment was satisfactory and the cases seemed to do quite as well as where other more active measures were employed.

On this coast only two medical officers were led to regard the disease as contagious. One considers it infectious and the others are of the opinion that influenza is not a contagious disease.

GULF COAST OF NORTH AMERICA.

But one report has been received from this region, viz, from the naval station at Pensacola, Fla., under date of March 5. The disease had not as yet been observed there.

VESSELS CRUISING IN THE WEST INDIES.

Three vessels cruising in the West Indies report no cases having occurred on board. During the time when the disease was epidemic in the United States these vessels were visiting ports in Haiti, Jamaica, and Cuba. Some cases of influenza were said to have occurred in these islands, but, if they were genuine cases at all, they were few in number and mild in character.

ATLANTIC COAST OF SOUTH AMERICA.

The only report from this region is from the steamer Tallapoosa, stationed at Montevideo, in Uruguay. The disease appeared on this vessel on February 1; the epidemic reached its height on February 20; and disappeared March 10, having prevailed 38 days. The complement of this vessel numbers 161 all told, and of this number 20 per cent were attacked. The prominent symptoms were neuralgia of the scalp, pain in the back, lumbar region, and along the sciatic nerve. There was marked anorexia. There were no eruptions, but sweating was a well-marked feature of the disease. Obstinate bronchitis was the only complication. There were no cases of pneumonia and no deaths. Quinine and antipyrine were the remedies used. It is the opinion of this medical officer that the disease is not contagious.

PACIFIC COAST OF NORTH AMERICA.

Reports from this coast were recieved as follows: Sitka, Alaska, 1; Mare Island, 4; San Francisco, 1; Oakland, 1.

Alaska.--In Alaska the disease did not appear in an epidemic form and no characteristic cases are reported. Nasal, pharyngeal, and bronchial catarrh are said to have been more frequent than usual.

San Francisco, Oakland, Mare Island.--Taking these reports collectively the first case occurred on January 1. From that time the disease spread and the epidemic attained its maximum of intensity about January 20. It then gradually

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declined, and by February 10 had subsided, having continued about 40 days.

Out of a force of about 1,000 men at the Marie Island naval station, 15 per cent suffered from the disease. Four cases of relapse were reported.

The most prominent symptoms were--

(a) Of the Nervous System.--Pain in lumbar region. Intercostal neuralgia. Supraorbital neuralgia with coryza, often confined to one side; cephalgia.

(b) Of the respiratory and circulator system.--Bronchitis with fever. Temperature first day, 102.5° to 103.5°, dropping to 101° on second day and normal on the third.

(c) Of the digestive organs.--Anorexia, coated tongue, constipation.

(d) Of the skin.--Relaxed skin; perspiration at intervals of several hours coincident with slight reduction of temperature. In some cases profuse perspiration upon departure of fever.

No special complications were observed, but there was extreme muscular debility out of proportion to the gravity of the disease and lasting for weeks.

In 150 cases of influenza, 11 cases of pneumonia occurred, all croupous.

The mortality was 4 per cent, all the deaths being caused by pneumonia.

Treatment.--Aperients, mineral acids, antipyrine, and quinine were the remedies employed and gave satisfactory results.

It is the opinion of the medical officers on the Pacific coast that the disease is not contagious.

A vessel lying at Oakland did not have any cases of influenza on board, though the disease was quite prevalent in the town.

HAWAIIAN ISLANDS.

A report from Honolulu states that the disease was still epidemic there as late as April 10, but the time when it first appeared is not stated.

At Canton, China, under same date (Apr. 10) the disease is reported not to have been observed.

Prevalence of Influenza in Recent Years.

Influenza appears to have become unusually prevalent again in the United States at least as early as 1916, when the death rate from this cause in the registration area was 26.4 per 100,000. This was an increase of 65 per cent over the rate for 1915, which was 75 per cent higher than that for 1914.

In 1917 the death rate for influenza was lower again--17.2 per 100,000. The rate for influenza, however, does not mean so much in years when the disease is not generally recogtnized, and it is significant that the death rate for all forms of pneumonia in the registration area in 1917 was 149.3 per 100,000, as compared with 137.3 in 1916, the highest rate since 1900. In 1900 the rate was 180.5, probably an influenza year, although the rate for influenza itself was higher in 1901 when it was 32.2.

The report of the registrar general of England and Wales for the year 1916 shows that the numbers of deaths from influenza reported by years from 1911 were as follows;

                       Deaths.
1911                      4,334
1912                      5,352
1913                      6,387
1914                      5,953
1915                      10,471
1916                      8,782

Thus the number of deaths reported in 1915 was nearly double that for preceding years.

Influenza was epidemic in various parts of Europe throughout 1918, and undoubtedly the earlier outbreaks were carried over from 1917. The files of The Lancet indicate that a more or less widespread

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epidemic occurred in England in the spring of 1915. The disease does not appear to have been as prevalent in 1916 as in 1915, but in 1917, among the military forces, cases of so-called "purulent bronchitis" occurred which were fundamentally the same as the rapidly fatal cases of influenzal pneumonia so frequently seen at the height of the pandemic.

An epidemic of purulent bronchitis was reported from a British Army base in northern France in January, 1917, whilst an epidemic of influenza was in progress. This outbreak began in December, 1916. Later, in the spring of 1917, similar cases of purulent bronchitis were treated at Aldershot, England. These cases are noteworthy because they seem to have been similar in all respects to the fatal types of influenzal pneumonia so commonly seen in all parts of the world during the autumn of 1918. The epidemic referred to was reported by Hammond, Rolland, and Shore in The Lancet, July 14, 1917. They remark that although the earlier cases were admitted during December, 1916, it was not until the end of the following January, when exceptional cold prevailed, that the disease assumed epidemic proportions. The disease was very fatal and was the cause of death in 45.5 per cent of 156 consecutive cases coming to necropsy. Clinically, the prominent signs were the characteristic yellow purulent or mucopurulent sputum, tachycardia, and cyanosis. The pathological findings were thick purulent material in the smaller bronchi from which frequently air was excluded; in some cases secondary broncho-pneumonia, edema, and emphysema. The lungs were almost always bulky. The cause of the disease was thought to be the Pfeiffer bacillus because of its almost constant occurrence in the sputum and in the pus in the bronchioles. In some typical cases it occurred apart from the presence of any other microorganism, although more frequently pneumococci or streptococci were associated with it.

Abrahams, Hallows, Eyre, and French in The Lancet, September 8, 1917, reported their observations of scores of similar cases in the Aldershot command. Their conclusions were almost identical with those recorded above. Case fatality rates were approximately 50 per cent. Stress was laid upon a peculiar dusky heliotrope type of cyanosis of the face, lips, and ears, as a characteristic sign. They found that whether cultures were made from the sputum itself or from material obtained by lung puncture, or from the blood or organs post mortem, influenza bacilli and pneumococci were constantly found and they conjectured that the disease started as an influenza bacillus infection, terminating in fatal cases as a pneumonococcus septicemia, the pneumococcus increasing its virulence by growth in symbiosis with B. Influenzae.

Because it was taken for granted that B. Influenzae was without lethal effect upon the lower animals no virulence estimations were attempted. However, two small rabbits were subjected to intrapulmonary inoculations with strains of B. Influenzae isolated from two mild cases of purulent bronchitis. The first rabbit died 12 hours later because of accidental puncture of a large vessel. The second experiment was successful, the rabbit dying on the fifth day with pleural effusion and lesions in the lungs. The polymorphonuclear leucocytes in the pleural fluid were packed with influenza bacilli and pure cultures of the micro-organisms were recovered from the lung tissues, heart, blood, and spleen.

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Later, in The Lancet, January 4, 1919, Abrahams, Hallows, and French reported in detail, "A further investigation into influenzo-pneumococcal and influenzo-streptococcal septicaemia" as seen during the epidemics of influenza in September and October, 1918. They concluded, after ample opportunities for broadening and extending their views, that the "purulent bronchitis' type is merely one of many and that the cases seen in 1916 and 1917 represent fundamentally the same condition as the fatal "influenzal pneumonia" seen at the height of the pandemic, in which, they believed, "influenzo-pneumococcal septicaemia" was responsible for most, if not all, fatal cases, it being only a matter of degree whether there occurred "purulent bronchitis," "capillary bronchitis" or "broncho-pneumonia."

Roughly speaking, among the cases of influenza seen at Aldershot, 80 per cent took an ordinary uncomplicated course and 20 per cent showed pulmonary complications in some degree. Eight per cent were moderately severe and 12 per cent of the patients were desperately ill. For the latter group the case-fatality rate was somewhere between 60 and 80 per cent. As compared with cases seen during the previous year they weres truck by the relative paucity and even absence of sputum, although in numerous instances typical cases of "purulent bronchitis" were also seen.

The 1918 Pandemic of Influenza.

Epidemics of Influenza in the Navy early in 1918.--reports received from time to time from various ships and stations of the Navy show that outbreaks of influenza began to occur early in 1918, in this country as well as abroad. A suspicious outbreak occurred on board the U.S.S. Minneapolis at the navy yard, Philadelphia, in January, 1918. There were 21 cases in all and the epidemic subsided in two weeks.

February, 1918.--Outbreaks were noted as follows:

             Cases.
U.S.S. Dubuque at the navy yard, New York   11
U.S.S. Madawaski, Cruiser and transport Force   37
U.S.S. New Jersey, Atlantic coast   220
U.S.S. Salem at the navy yard, Boston   30
United States Naval Radio School, Cambridge, Mass.   350-400

Eleven cases of pneumococcus-streptococcus pneumonia were associated with the outbreak at the Harvard Radio School in Cambridge. In the same month several cases of influenza complicated with streptococcus pneumonia occurred at the navy yard, Portsmouth, N.H., among the crew of the U.S.S. South Dakota and cases of epidemic influenza without complications occurred among the crew of the U.S.S. Leonidas at the same yard.

March, 1918--

             Cases.
U.S.S. Frederick at the navy yard, Portsmouth, N.H.   147
U.S.S. St. Louis at Norfolk, Va.   73
U.S.S. Charleston at Hampton Roads, Va.   55
U.S.S. Buffalo at Philadelphia, Pa.   21

The prevalence of influenza in epidemic form was also reported from the U.S.S. Georgia and the U.S.S. Kansas, Chesapeake Bay.

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April, 1918.--

U.S.S. North Carolina at Norfolk, Va.; 100 cases of a mild type.

U.S.S. Pensacola at the navy yard, Charleston, S.C.; mild epidemic; cases of short duration.

U.S.S. May, base 20, Rochefort, France, 25 per cent of the crew suddenly attacked.

U.S.S. Oregon at Mare Island, Cal., approximately 450 men, two-thirds of the ship's company attacked by influenza.

U.S.S. Bath, Hampton Roads, Va.; 38 cases with 1 death.

United States Naval Training Camp, Gulfport, Miss.; mild epidemic but higher percentage of complement attacked than during the subsequent fall epidemic.

Seventh Regiment, United States Marine Corps, Santiago de Cuba; mild epidemic which spread rapidly. Men who were attacked at this time apparently possessed immunity later, during the fall and winter.

United States Submarine Base, San Pedro, Cal.; an epidemic of 10 days' duration following the visit of a Japanese ship on board which the disease was prevalent.

United States Naval Training Camp, San Diego, Cal.; following the visit of a Japanese Squadron an epidemic occurred on the station; 9 per cent of the complement were attacked, 410 cases. Pneumonia complicated in 12 cases.

May, 1918.--

    Cases.
U.S.S. Dixie, Queenstown, Ireland (11 per cent of the crew attacked)   77
U.S.S. Texas, with British Grand fleet 92 deaths)   80
U.S.S. Birmingham at Gibraltar 910-day epidemic)   78
U.S.S. Chester at Plymouth, England (20 per cent of the crew affected)   80
U.S.S. Nashville, Passage, Gibraltar to Bizerti, Africa (47 per cent of the crew attacked)   91
United States Naval Air Station, Dunkirk, France (90 per cent of the complement attacked)    
United States Naval Air Station, Gujan-Mestras, France (40 per cent of the complement attacked)   72

Severe epidemics occurred in China in the Yangtze Valley, in the vicinity of Shanghai and in Peking, in May, June, and August. In September, October, and November epidemics prevailed throughout China causing high mortality rates.

June, 1918.--

    Cases.
U.S.S. Machias at Gibraltar (25 per cent of the crews attacked)   63
U.S.S. Brooklyn at Vladivostok, Siberia (successive epidemics for 8 weeks)    
U.S.S. Monterey, Pearl Harbor, Hawaii (66 per cent of the crew attacked)   124
U.S.S. Castine at Gibraltar (18 per cent of the crew attacked)   32
U.S.S. New York with British Grand Fleet (10 percent of the crew attacked, serious pulmonary complications in 8 per cent of the cases, 2 deaths)   138

    Cases.
U.S.S. Tallahassee at Key West, Fla. (20 per cent of the crew attacked)   76
U.S.S. Dubuque at navy yard, New York (5 per cent of the crew attacked)    
U.S.S. Plattsburg, Atlantic Transport Service (sporadic cases occurred throughout the month.)    
U.S.S. Galatea, Azores (50 per cent of the crew attacked)   30
U.S.S. Venetia at Gibraltar (19 per cent of the crew attacked)   16
United States Naval Air Station, Wexford, Ireland, epidemic of 2 weeks' duration   65
United States Naval Air Station, L'Abervrach Finisterre, France   69
United States Naval Air Station, Fromentine, Vendée, France (mild epidemic of 2 weeks' duration)   32
United States Naval Air Station, Queenstown, Ireland (epidemic began July; cases occurred to November 1)   243
United States Naval Air Station, Guipavas, France   26
United States Naval Air Station, La Trinité France (28 per cent of the complement attacked, 2 cases of complicating pneumonia)   40

--2424--

August, 1918.--

    Cases.
United States Naval Air Station, St. Trojan, France (63 per cent of the complement affected at one time, 20 cases of complicating pneumonia, 1 of meningitis; 5 deaths)   215
United States Naval Station, Cristobal, Canal Zone (epidemic of the pandemic type appeared will before progressive spread began in the United States)    

At the navy yard, Mare Island, Cal., the admission rate per 1,000 for influenza for the year 1918 was 259.8, as compared with 6.9 for 1915, 1.9 for 1916, and 35.9 for 1917. Excluding the fall epidemic, the admission rate for 19187 would have been 62.9 per 1,000, which indicates that influenza was undoubtedly on the increase long before the storm broke in October.

The monthly curve for influenza at that station during the year 1918 shows a higher mark in January than in December, 1917. The curve rose sharply to an apex in March, 1918, and then fell abruptly, so that in May it as much lower than in January. It then rose slowly through June, July, and August, reaching the level of January in the latter month. An unaccountable drop occurred in September to the lowest point reached during the year. This was followed by a tremendous rise in October; then a drop to nearly one-half in November and a still further drop in December, when the curve again reached the level of January.

In the sanitary report from United States Navy Yard, Mare Island, Cal., for the month of July, 1918, it was noted that "practically all cases of pneumonia developed among detentioners, * * * and among those quartered in the barracks (naval training camp barrack building)." "All had been treated for influenza or 'colds' and most of the cases were sent to hospital with a diagnosis of influenza or bronchitis and the diagnosis was changed at the hospital to pneumonia as the result of later developments." "Most of the pneumonia cases were atypical, suggesting the bronchial type, and there was no case of frank lobar pneumonia."

During the month of March, 1918, 1,066 employees of the Ford Motor Co., detroit, Mich., were sent home from the factory with influenza. The number of cases gradually increased from 10 on March 1 to 54 on March 27, and 145 on March 28. From March 289 to April 8, an average of 168 cases occurred. April 9 a sudden drop to 65 took place and thereafter the incidence continued to lessen until May 8, when the number of cases dropped to 10, which seemed to be the average number of cases occurring normally at that time. It was estimated that the number of patients sent home from work represented about half the total number of cases occurring among employees. During this spring epidemic the average time lost per patient was 3.57 days.

Several cargo vessels from Europe arrived in Philadelphia early in the summer with influenza cases on board. From the British steamship City of Exeter, arriving at Philadelphia June 22 from Liverpool, 27 lascars and an English quartermaster were removed to hospital desperately ill with pneumonia. Two steamships from Norway and another from some Scandinavian port arrived in New York August 14 and 15 with a number of patients ill with influenza. The Norwegian liner Bergensford,, arriving at New York August 12, reported a large number of cases resembling influenza during passage. At about the same time a steamship arrived at Newport News with almost the entire crew affected. A liner, arriving at New York August 18, reported the development of 21 cases of influenza among passengers and crew during the voyage. During the month of August a sharp outbreak occurred at Fort Morgan, Ala.

--2425--

By the middle of July it was evident from weekly statistics of the Navy and reports from ships and stations, as well as reports from Spain, Austria, Germany, Switzerland, France, Great Britain, Hawaii, and elsewhere, that influenza was again pandemic, but at that time it could not be foretold that epidemics were shortly to occur associated with a type of pneumonia scarcely equalled in intensity of infection by anything except the pneumonic form of plague and causing case-fatality rates for influenza exceeding 4 per cent in many localities.

Late in August the type of cases changed; the disease began to spread progressively from one community to another. The percentage of pulmonary complications increased beyond comparison with regard to the earlier epidemics, and influenzal pneumonia frequently began very early in the disease.

The effect of influenza on the crude death rate of the Navy is strikingly shown on chart No. 1 on page 355 and chart No. 2 on page 356.

In the United States the first cases of this phase of the pandemic were recognized in the receiving ship at Boston, Mass. (Commonwealth Pier). Scattered cases of the same type had appeared among the civilian population of Boston earlier, but the serious nature of the disease was not recognized until after the beginning of the great epidemic.

It is possible that the causative agent of influenza was introduced afresh from European ports among the personnel of the receiving ship, but no particular vessel was recognized as being responsible for the introduction leading to the outbreak in question.

Epidemics of like character occurred almost simultaneously in most parts of the world. In the Canal Zone a rapidly spreading epidemic occurred even before progressive spread began in the United States. The epidemic in China began in the latter part of August. By September 1, serious epidemics were in progress in South Africa, India, and Japan, as well as in many parts of Europe. Influenza of malignant type was apparently introduced into Rio de Janeiro, Brazil, from Spain, September 17, by the ship Demerara, sailing from Lisbon, Portugal, via Dakar, Africa. The epidemic in Spain had got well ahead in May. In Switzerland the epidemic began suddenly about July 1, and during July 53,698 cases of influenza were reported, as compared with 34 cases for the previous six months. In succeeding months cases were reported as follows: August, 41,626; September, 41,642; October 263,399; November, 159,422; and December, 104,612.

A comparatively mild epidemic of influenza and pneumonia prevailed in France from April 1 to August 1. About August 22 a violent outbreak began among the French forces in the vicinity of Brest. The comparatively mild earlier epidemic had apparently subsided about August 1, and the French authorities decided to continue the enrollment of the class of 1920. In the latter part of the month the violent epidemic mentioned began and reached its height in September, the pneumonia continuing into October.

It might be concluded that the cases of purulent bronchitis which occurred in northern France and England in 1917 were forerunners of the severe types of influenza which were so numerous during the

--2426--

Chart 6
Chart 6:U.S. Navy.
Influenza Epidemics--1918.
Case Incidence per 1000 of Complement by Days
at Seventeen of the Larger Shore Stations in the United States


fall of 1918. Influenza probably continued in epidemic form in France during 1917 and the spring of 1918, when it spread to Spain. In Spain the disease spread more rapidly and more extensively, and about July 1 was introduced into Switzerland either from this source or directly from France. The more serious epidemic in France, which began in August, 1918, may have been due to return spread from Spain or Switzerland or both. At any rate, it is reasonable to suppose that late in August influenza of severe type was spread from French, Spanish, and Portuguese seaports to the Orient, South Africa, the United States, and South America.

EPIDEMICS OF INFLUENZA IN THE NAVY DURING THE AUTUMN OF 1918.

The epidemic at Commonwealth Pier, the receiving ship at Boston, may be said to have begun August 27, 1918, when three cases of influenza were admitted to the sick list, although naturally they were not recognized on that day as the beginning of rapidly spreading outbreaks in the Navy with increasing case-fatality rates. The following day 8 cases occurred, and on August 29, 58 cases, of which 50 were transferred to the United States Naval Hospital Chelsea, Mass., where cases among the medical staff began to occur in less than 48 hours.

The early cases occurring during the outbreaks at naval stations in the first naval district in the vicinity of Boston were characterized by very sudden onset, patients, frequently passing within a hour or two from an apparent healthy condition into a state of prostration.

At Commonwealth Pier the peak of the epidemic was reached on the sixth day and the major phase was over on the eighth day. Outbreaks followed promptly in practically all naval stations in the vicinity of Boston. No grouping or localization of cases could be detected at any station, nor could any relationship be traced between attacks at one station or ship and another. Between the naval radio school, Harvard University, where an extensive epidemic occurred, and Commonwealth Pier, where the first cases appeared, there was little contact. There was close relationship between Commonwealth pier and the Boston section base, as well as the naval aviation detachment in Cambridge, in both of which stations comparatively few cases occurred, while epidemics were in progress at other stations near by.

At the training camp on Bumkin Island, well out in the harbor, a short but severe epidemic began September 7, reaching its highest peak two days later and a second high peak September 12, after a decrease in the number of new cases September 11. The outbreak declined suddenly September 13, and was practically over by September 16.

The disease appeared in the navy yard, Portsmouth, N.H., in the course of a few days, where the greatest incidence was in the naval prison.

At the United States Naval Training Station, Newport, R.I., the epidemic began September 10, reached its peak seven days later, and terminated on the sixteenth day. The earliest cases among naval personnel in Newport occurred at the training station.

September 11, 22 cases appeared at the submarine base and 50 at the naval district base, New London, Conn.

--2427--

At this time, with the exception of the receiving ship, naval stations in the vicinity of New York City escaped epidemics for the most part, the outbreak at the United States Naval Training Camp, Pelham Bay Park, not beginning until September 24.

Influenza was probably introduced into the navy yard, Philadelphia, Pa., September 6, by a draft of men from Boston, 6 cases developing September 11 among the receiving ship personnel. A draft of several hundred men left the navy yard, Philadelphia, for Quebec on September 10 and six cases of influenza developed among them upon arrival at Quebec, September 11.

The outbreak in the receiving ship at Philadelphia was severe. The greatest number of cases occurred on the fifth day, but the epidemic did not begin to subside until the tenth day.

On September 11, epidemics also began at the marine barracks, Quantico, Va.; navy yard, Charleston, S.C.; and at the United States Naval Station, Pensacola, Fla. The epidemic began at G reat Lakes S eptember 12; September 13, at the naval training station, Hampton Roads, Va.; September 16, at the receiving ship and naval station, Norfolk, Va.; also at Wissahickon Barracks, Cape May, N.J.

September 17, the disease was introduced into the navy yard, Puget Sound, Wash., by a draft of 334 men from the navy yard, Philadelphia, Pa., 11 of whom were ill with influenza upon arrival. The disease became epidemic in the city of Seattle and at the naval training camp in Seattle about September 25.

A severe epidemic began at the naval station, New Orleans, La., September 26. At the naval training camp, Gulfport, Miss., an outbreak occurred September 28, and this also proved to be relatively severe.

As mentioned above, a mild but somewhat extensive epidemic of influenza occurred at the naval training camp, San diego, Cal., in the spring of 1918. The disease was prevalent all through the month of September, the number of cases from September 1 ranging from 2 or 3 to 10 on September 9. From that day there was a g radual increase to 35 cases on September 18, after which the number of new cases per day decreased slightly until September 24 when 33 cases occurred, increasing to 80 new cases September 25, which marked the peak of a relatively mild epidemic. Apparently the course of the epidemic at this station was modified by the presence of men who had passed through the spring epidemic.

Influenza was introduced into the navy yard, Mare Island, Cal., September 25, by a man who became ill on the train returning from leave in Oklahoma. The health officer of San Francisco reported to the naval authorities that six cases had occurred in the city during the week ending September 21.

To recapitulate, epidemics began at naval stations in the United States as follows:

Receiving ship, Boston Aug. 28.
Harvard Radio School, Cambridge, Mass. Sept. 4.
Bumkin Island, Boston, Mass. Sept. 7.
Navy yard, Portsmouth, N.H. Sept. 7.
Naval training station, Newport, R.I. Sept. 10.
Submarine base and naval district base, New London, Conn. Sept. 11.
Navy yard, Philadelphia, Pa. Sept. 11.
Marine barracks, Quantico, Va. Sept. 11.
Navy yard, Charleston, S.C. Sept. 11

--2428--

Chart No. 7
Chart No. 7
Logarithmic scale of ordinates (rates); arithmetic scale for abscissae (weeks). Certain shore stations of the Navy in the United States. Annual death rates by weeks, September 1 to December 31, 1918, influenza, including influenzal pneumonia.


Naval station, Pensacola, Fla. Sept. 11.
Naval training station, Great Lakes, Ill. Sept. 11.
Naval training station, Hampton Roads, Va. Sept. 13.
Receiving ship, New York Sept. 15.
Receiving ship, Norfolk (St. Helena Station) Sept. 16.
Wissahickon barracks, Cape May, N.J. Sept. 16.
Navy yard, Puget Sound, Wash. Sept. 17.
Naval training camp, Pelham Bay Park, N.Y. Sept. 24.
Naval training camp, Seattle, Wash. Sept. 25.
Navy yard, Mare Island, Cal. Sept. 25.
Naval station, New Orleans, La. Sept. 26.
Naval training camp, Gulfport, Miss. Sept. 28.

The general characteristics of the outbreaks at shore stations in the United States in respect to time of onset, duration and comparative incidence are shown in chart No. 6, indicating the incidence per thousand of complement by days, the curves covering the major epidemic at each station within the period, August 27 to December 31, 1918.

Charts Nos. 7 and 8 show annual death rates by weeks, epidemic period, September 1 to December 31, 1918, influenza (including influenzal pneumonia) for each of the 17 stations for which the influenza case-incidence rate by days is shown in chart No. 6.

Each station is represented by a color, and the same color is used for that station in both the morbidity curve and the mortality curve.

Charts Nos. 9 and 10 show annual death rates (all causes) by weeks during the epidemic period, for certain cities of the United States. The data were obtained from the weekly index published by the United States Bureau of the Census. Comparisons may be made because the excess mortality in these cities during the epidemic period was due almost, if not entirely, to influenza.

A striking feature of most of the epidemics at naval stations was the rapidity of onset and the rapidity with which the peak of the epidemic was reached. The character of the onset was frequently very similar to outbreaks of scarlet fever and other diseases, in instances traced to a common source of infection. The peak of the epidemic was usually reached in from 6 to 10 days.

Table No. 1 shows the accumulated percentages of complements attacked day by day from the first day of the epidemic at each of 17 of the larger shore stations of the Navy in the United States.

Table No. 2 shows cumulative case fatality rates per 100 of complement, influenza, including influenzal pneumonia, by five-day periods fro 15 stations.

Table No. 3 shows the epidemic influenza attack rate per 1,000, the epidemic death rate per 1,000, and the case-fatality rate per 100, all cases of influenza, including influenzal pneumonia, for the period of the primary epidemic at each of these stations.

Annual death rates, by weeks, during the epidemic are shown for these stations in Table No. 4.

Table No. 5 shows annual death rates per 1,000 by weeks, for pneumonia, all forms, exclusive of influenzal pneumonia, for the same stations.

Table No. 6 shows the death rate per 1,000 during the 25 weeks, September 7 to March 1, inclusive, epidemic period in the United States, for 42 cities, from influenza and pneumonia (all forms) United States Bureau of the Census figures.

--2429--

TABLE NO. 1--Cumulative attack rate per 100 of complement by days
at 17 stations of the United States Navy.

Name of station, and average complement per week. First day Second day Third day Fourth day Fifth day Sixth day Seventh day Eighth day Ninth day Tenth day Fif
teenth
day
Twen
tieth
day
Twenty-
fifth
day
Thir
tieth
day
Receiving ship, Boston, 5,137; 4,794; 4,543; 4,585; 3,872; 3,798 0.15 1.28 2.66 3.85 6.02 8.19 9.86 10.09 10.57 10.84 12.34 14.74 15.33 18.95
Training camp, Bumkin Island, Boston, Mass., 973; 998; 992; 905; 1,897; 798 .20 .71 1.13 1.74 2.15 4.00 14.96 19.13 20.54 24.35 29.28 (1) (1) (1)
Training station, Newport, R.I., 10,183; 9,226; 9,070; 9,032 .14 .54 1.78 3.59 5.80 8.88 10.36 11.16 12.78 13.98 16.99 17.21 17.24 .....
Training station, Pelham Bay Park, N.Y., 14,816; 14,521; 14,309; 13,708; 13,678; 13,062 .01 .16 .51 .88 1.20 1.60 2.19 3.26 3.99 5.33 12.64 15.45 17.69 18.48
Receiving ship at Philadelphia, 6,658; 6,411; 6,352; 6,491; 6,260; 5,984 .09 1.05 2.07 3.46 5.70 7.73 8.98 10.65 12.54 14.20 16.98 17.96 19.21 20.01
Training camp (Wissahickon Barracks), Cape may, N.J., 1,790; 1,650; 1,536; 1,491; 1,481 .33 1.00 1.11 2.79 4.46 6.15 7.93 8.30 8.54 8.66 9.96 10.28 10.73 10.90
Marine barracks, Quantico, Va., 10,000; 8,650; 9,150; 7,700; 7,928; 6,700 .14 .50 1.24 3.05 4.76 6.11 7.90 9.38 9.92 11.79 17.06 25.54 26.70 26.70
Training station, Great Lakes, Ill., 45,515; 44,834; 44,901; 44,350; 43,427 .02 .04 .14 .51 1.06 2.04 3.23 5.85 8.52 10.93 18.65 20.71 21.34 21.85
Receiving ship, including St. Helena, Norfolk, Va., 8256; 8,039; 7,797 .04 .15 .29 .76 1.18 1.93 2.51 3.23 4.91 6.35 10.21 11.97 12.58 ......
Training station, Hampton Roads, Va., 10,929; 10,868; 11,817; 11,404; 10,821 .03 .10 .22 .92 1.48 2.23 3.61 4.78 5.74 7.14 17.12 23.41 27.53 ......
Training camp, Charleston, S.C., 4,056; 3,930; 3,877; 4,147; 4,268; 4,222 .42 .91 1.32 2.03 2.58 2.93 3.36 3.78 4.02 4.32 5.92 7.46 8.23 8.55
Training camp, Seattle, Wash., 4,248; 4,128; 4,100; 4,066, 4,076 2.37 3.27 5.88 8.35 11.09 12.54 13.83 14.55 15.23 16.01 17.90 19.03 19.77 ......
Training camp, Gulfport, Miss., 1,747; 1,731; 1,624; 1,723; 2,035; 1,901 1.31 2.07 3.63 6.35 8.55 11.20 15.94 18.94 24.63 29.98 45.07 46.19 43.42 ......
Training camp, San Diego, Cal., 5,025; 5,252; 4,688; 4,856 .03 .07 .17 .21 .23 .33 .41 .45 .64 .74 1.82 4.94 8.57 13.01
Training station, Puget Sound, Wash., 6,023; 6,488; 6,360; 6,601; 6,380 .04 .24 .36 .76 .96 .90 1.12 1.41 2.06 3.23 7.09 7.89 8.42 8.72
Naval station, Pensacola, Fla., 5,047; 5,223; 5,266; 5,359; 5,686; 5,558 .33 .69 .95 1.26 1.51 1.99 2.58 3.21 3.71 4.11 9.74 18.41 24.27 24.88
Training camp, New Orleans, La., 2,250; 2,864; 2,564; 2,514; 2,521; 2,177 .13 .93 2.88 4.85 7.71 9.91 11.69 13.58 16.06 19.37 32.39 35.09 37.14 37.80
1 Material influx of new men.

--2430--

Chart No. 8
Chart No. 8
Logarithmic scale. Certain shore stations of the Navy in the United States. Annual death rates by weeks, September 1, to December 31, 1918, influenza, including influenzal pneumonia.


TABLE NO. 2--Cumulative case-fatality rates per 100 of complement at 15 stations of the United States Navy.

Name of station. Fifth day. Tenth day. Fifteenth day. Twentieth day. Twenty-
fifth day.
Thirtieth day.
Receiving ship, Boston, Mass. 1.64 2.88 3.75 4.00 ...... ......
Training station, Newport, R.I. .41 2.10 4.28 5.35 ...... ......
Marine barracks, Quantico, Va. .98 1.86 2.55 3.35 3.78 3.92
Training station, Pelham Bay Park, N.Y. 1.24 3.56 4.59 5.01 5.02 5.06
Training station, Puget Sound, Wash. 1.56 4.58 7.86 10.17 10.68 10.86
Training station, Great Lakes, Ill. .47 2.77 6.58 8.00 8.60 8.78
Training camp (Wissahickon Barracks), Cape May, N.J. 5.45 8.90 9.03 10.12 ...... ......
Receiving ship at Philadelphia 1.31 3.89 5.23 5.55 5.67 5.69
Training camp, Bumpkin Island, Mass. .39 2.73 2.66 2.95 ...... ......
Training camp, Seattle, Wash. .19 .84 2.55 3.62 3.85 ......
Training camp, Gulfport, Miss. 1.04 1.55 1.85 2.06 ...... ......
Naval station, Pensacola, Fla. .42 .59 .85 1.05 ...... ......
Training camp, Charleston, S.C. .32 .72 1.81 1.69 1.54 1.46
Training camp, New Orleans, La. .45 .54 1.44 3.70 4.59 4.60
Training station, Hampton Roads, Va. .54 1.89 3.24 4.37 ...... ......
Name of station. Thirty-fifth day. Fortieth day. Forty-fifth day. Fiftieth day. Fifty-fifth day. Sixtieth day. Sixty-fifth day.
Marine barracks, Quantico, Va. 3.84 3.59 3.47 3.72 3.70 3.90 ......
Training camp, Charleston, S.C. 1.66 1.74 1.63 1.57 1.73 1.97 2.12

TABLE NO. 3--Influenza epidemic incidence rates, epidemic death rates, and case-fatality rates at 17 stations of the United States Navy.

Station. Duration of epidemic in days. Number of cases of influenza. Number of deaths. Epidemic influenza attack rate per 1,000. Epidemic death rate per 1,000. Case fatality rate influenza, period of epidemic. Average complement during epidemic.
Marine barracks, Quantico, Va. Sept. 9-Nov. 22
75 days
3,056 117 370.69 14.19 3.82 8,244
Training station, Newport, R.I. Sept. 10-Sept. 24
15 days
1,449 113 152.63 11.90 7.79 9,493
Training station, Pelham Bay Park, N.Y. Sept. 21-Oct 21
29 days
2,399 145 168.94 10.21 6.04 14,200
Training station, Puget Sound, Wash. Sept. 17-Oct. 10
24 days
568 60 89.16 9.41 10.55 6,370
Training station, Great Lakes, Ill. Sept. 12-Oct 11
30 days
9,623 924 215.73 20.71 9.60 44,605
Training camp. Wissahickon Barracks, Cape May, N.J. Sept. 23-Oct 4
12 days
150 14 87.20 8.13 9.33 1,720
Receiving ship at Philadelphia Sept. 11-Oct. 9
29 days
1,246 78 193.96 12.12 6.26 6,434
Training camp, Bumkin Island, Boston, Mass. Sept. 7-Sept. 15
9 days
251 11 260.37 11.41 4.38 964
Training camp, Seattle, Wash. Sept. 25-Oct 8
15 days
724 34 174.12 8.17 4.69 4,158
Naval station, Pensacola, Fla. Sept. 15-Oct 15
31 days
1,393 24 257.10 4.42 1.72 5,418
Training camp, New Orleans, La. Sept. 26-Oct 24
29 days
952 33 374.50 12.98 3.46 2,542
Training camp, Charleston, S.C. Sept. 11-Nov. 16
67 days
1,118 26 265.89 6.23 2.23 4,167
Receiving ship, Boston Aug. 28-Oct 1
35 days
804 52 180.46 11.67 6.46 4,454
Training camp, San Diego, Cal. Sept.. 8-Spet. 30
23 days
628 19 127.34 3.85 3.02 4,932
Training station, Hampton Roads, Va. Sept. 15-Oct. 9
25 days
3,005 175 270.62 15.76 5.82 11,104
Receiving ship, including St. Helena, Norfolk, Va. Sept. 16-Oct 6
21 days
991 69 123.96 8.63 6.96 7,994
Training camp, Gulfport, Miss. Sept. 28-Oct 24
27 days
822 18 463.88 10.15 2.18 1,772
   
Combined rates--all stations   29,179 1,912 205.23 13.44 6.56 142,171

--2431--

TABLE NO. 4.--Annual death rates per 1,000, by weeks, influenza (including influenzal pneumonia), Sept. 1 to Dec. 31, 1918, inclusive; for 17 of the larger stations of the Navy in the United States.

Week. Training camp, Pelham Bay Park, N.Y. Training station, Great Lakes, Ill. Training camp, San Diego, Cal. Training camp, Charleston, S.C. Training station, Hampton Roads, Va. Training station, Norfolk, Va.
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 14 ------ ------ 1 1.09 ------ ------ ------ ------ ------ ------ ------ ------
Sept. 21 1 3.43 97 112.32 1 10.92 1 13.00 ------ ------ ------ ------
Sept. 28 ------ ------ 489 566.28 ------ ------ 5 66.56 19 86.84 8 51.48
Oct. 5 13 46.28 197 230.88 1 10.40 2 24.96 66 312.00 37 243.88
Oct. 12 64 232.44 58 69.16 ------ ------ 2 23.92 47 227.24 18 119.60
Oct. 19 31 117.52 18 21.32 2 20.80 4 48.88 23 107.64 2 13.52
Oct. 26 10 37.96 15 18.20 ------ ------ 3 35.88 3 13.52 1 6.76
Nov. 2 3 12.48 9 11.44 1 10.40 1 11.44 4 19.24 1 6.76
Nov. 9 2 8.84 5 6.76 2 20.80 3 36.40 4 19.76 1 6.24
Nov. 16 1 4.73 9 13.00 5 56.68 3 36.40 1 4.88 ------ ------
Nov. 23 ------ ------ 6 8.84 1 12.48 1 11.96 ------ ------ ------ ------
Nov. 30 ------ ------ 2 3.22 2 24.96 ------ ------ ------ ------ ------ ------
Dec. 7 ------ ------ 3 4.94 2 26.00 ------ ------ 1 3.79 ------ ------
Dec. 14 2 6.76 5 7.80 2 26.52 1 16.12 5 18.72 ------ ------
Dec. 21 4 11.44 4 6.24 ------ ------ ------ ------ 2 7.28 1 7.28
Dec. 28 10 32.76 3 4.78 ------ ------ ------ ------ ------ ------ ------ ------
Dec. 29-31 4 32.94 3 11.59 ------ ------ ------ ------ ------ ------ ------ ------
Total 145 31.56 924 72.12 19 12.69 26 20.25 175 44.94 69 27.15
Week. Training camp, Puget Sound Wash. Training camp, Cape May, N.J. Receiving ship, Philadelphia Training camp, Bumkin Island, Mass. Training camp, Gulfport, Miss. Training camp, Seattle, Wash.
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 14 ------ ------ ------ ------ 1 7.80 1 52.00 ------ ------ ------ ------
Sept. 21 ------ ------ ------ ------ 14 113.36 6 338.00 ------ ------ ------ ------
Sept. 28 7 55.64 6 174.20 29 237.12 1 57.20 1 29.64 2 24.44
Oct. 5 24 195.52 7 220.48 12 95.68 1 27.04 ------ ------ 3 37.44
Oct. 12 20 157.04 1 33.80 13 107.64 ------ ------ 2 63.96 20 253.24
Oct. 19 5 40.56 ------ ------ 5 43.16 ------ ------ 13 392.08 3 37.96
Oct. 26 1 7.80 ------ ------ ------ ------ ------ ------ 2 50.96 2 25.48
Nov. 2 1 8.32 ------ ------ ------ ------ 1 52.52 ------ ------ 3 38.48
Nov. 9 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 16 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 23 2 18.20 ------ ------ 1 7.28 ------ ------ ------ ------ ------ ------
Nov. 30 ------ ------ ------ ------ 1 7.28 ------ ------ ------ ------ ------ ------
Dec. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 14 ------ ------ ------ ------ ------ ------ 1 62.40 ------ ------ 1 11.44
Dec. 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 28 ------ ------ ------ ------ 2 21.84 ------ ------ ------ ------ ------ ------
Dec. 29-31 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 60 30.90 14 24.30 78 37.26 11 30.27 18 32.46 34 24.45

--2432--

Chart No. 9
Chart No. 9--Logarithimic scale. Certain cities in the United States. Annual death rates for all causes, by weeks during the epidemic period.


TABLE NO. 4.--Annual death rates per 1,000, by weeks, influenza, etc.--Con.

Week. Receiving ship, Boston, Mass. Training station, Newport, R.I. Marine barracks, Quantico, Va. Training station, New Orleans, La. Naval station, Pensacola, Fla. Total
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 8 86.32 ------ ------ ------ ------ ------ ------ ------ ------ 8 2.96
Sept. 14 19 217.36 2 9.88 ------ ------ ------ ------ ------ ------ 24 8.32
Sept. 21 14 158.60 27 151.84 1 5.72 ------ ------ ------ ------ 162 59.28
Sept. 28 5 67.08 55 315.12 25 141.96 ------ ------ 1 9.36 653 243.36
Oct. 5 4 54.60 23 132.08 22 148.20 1 17.68 9 86.84 422 159.12
Oct. 12 ------ ------ 5 30.16 20 131.04 11 223.08 10 91.00 291 111.80
Oct. 19 ------ ------ ------ ------ 9 69.68 12 248.04 3 27.56 130 50.96
Oct. 26 ------ ------ ------ ------ ------ ------ 6 123.76 ------ ------ 43 16.64
Nov. 2 ------ ------ ------ ------ ------ ------ 2 47.32 ------ ------ 26 10.40
Nov. 9 ------ ------ ------ ------ 13 75.92 ------ ------ ------ ------ 30 11.96
Nov. 16 ------ ------ ------ ------ 9 58.76 ------ ------ ------ ------ 28 11.44
Nov. 23 ------ ------ ------ ------ 16 139.96 ------ ------ ------ ------ 25 9.36
Nov. 30 1 8.84 ------ ------ 1 5.20 ------ ------ ------ ------ 9 3.79
Dec. 7 1 7.80 ------ ------ 1 5.20 ------ ------ ------ ------ 8 3.27
Dec. 14 ------ ------ ------ ------ ------ ------ 1 28.08 ------ ------ 18 7.28
Dec. 21 ------ ------ ------ 1 8.32 ------ ------ ------ ------ ------ 12 4.99
Dec. 28 ------ ------ ------ ------ ------ ------ ------ ------ 1 9.36 16 6.76
Dec. 29-31 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 7 7.68
Total 52 34.74 113 45.72 117 40.77 33 45.06 24 13.29 1,912 44.40

TABLE NO. 5--Annual death rates per 1,000, by weeks, pneumonia (all forms exclusive of influenzal pneumonia), Sept. 1 to Dec. 31, 1918, inclusive, for 17 of the larger stations of the Navy in the United States.

Week. Training camp, Pelham Bay Park, N.Y. Training station, Great Lakes, Ill. Training camp, San Diego, Cal. Training camp, Charleston, S.C. Training station, Hampton Roads, Va. Training station, Norfolk, Va.
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 14 ------ ------ 2 2.36 ------ ------ ------ ------ 1 4.73 1 6.24
Sept. 21 ------ ------ 3 3.43 ------ ------ ------ ------ ------ ------ ------ ------
Sept. 28 ------ ------ 14 16.12 ------ ------ 2 26.52 ------ ------ ------ ------
Oct. 5 ------ ------ 4 4.68 ------ ------ 1 12.48 1 4.68 ------ ------
Oct. 12 3 10.40 1 1.96 ------ ------ ------ ------ ------ ------ ------ ------
Oct. 19 4 15.08 2 2.39 ------ ------ ------ ------ 1 4.68 ------ ------
Oct. 26 ------ ------ 2 2.44 ------ ------ ------ ------ ------ ------ 1 6.76
Nov. 2 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 9 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 16 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 23 ------ ------ 1 1.50 ------ ------ ------ ------ ------ ------ ------ ------
Nov. 30 1 4.42 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 7 ------ ------ 2 3.27 ------ ------ ------ ------ ------ ------ ------ ------
Dec. 14 ------ ------ 1 1.61 ------ ------ ------ ------ ------ ------ ------ ------
Dec. 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 28 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 29-31 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 8 1.74 32 2.49 ------ ------ 3 2.31 3 .75 2 .68

--2433--

TABLE NO. 5--Annual death rates per 1,000, by weeks, pneumonia etc.--Con.

Week. Training camp, Puget Sound Wash. Training camp, Cape May, N.J. Receiving ship, Philadelphia Training camp, Bumkin Island, Mass. Training camp, Gulfport, Miss. Training camp, Seattle, Wash.
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 14 ------ ------ ------ ------ 1 8.84 ------ ------ ------ ------ ------ ------
Sept. 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 28 1 7.80 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Oct. 5 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Oct. 12 ------ ------ ------ ------ ------ ------ ------ ------ 4 127.92 2 24.96
Oct. 19 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 1 12.48
Oct. 26 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 2 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 9 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 16 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 23 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 30 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 14 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 28 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 29-31 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 1 .51 ------ ------ 1 .45 ------ ------ 4 7.20 3 2.13
Week. Receiving ship, Boston, Mass. Training station, Newport, R.I. Marine barracks, Quantico, Va. Training station, New Orleans, La. Naval station, Pensacola, Fla. Total
Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate. Deaths. Rate.
Sept. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Sept. 14 2 22.88 ------ ------ ------ ------ ------ ------ ------ ------ 7 2.54
Sept. 21 1 10.92 2 10.92 ------ ------ ------ ------ ------ ------ 6 2.23
Sept. 28 ------ ------ ------ ------ 1 6.24 ------ ------ ------ ------ 23 8.32
Oct. 5 ------ ------ ------ ------ 1 6.24 ------ ------ ------ ------ 7 2.60
Oct. 12 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 10 3.84
Oct. 19 ------ ------ ------ ------ 1 7.28 ------ ------ ------ ------ 9 3.53
Oct. 26 ------ ------ ------ ------ 1 7.80 ------ ------ ------ ------ 4 1.76
Nov. 2 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 9 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 16 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Nov. 23 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 1 .39
Nov. 30 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 1 1.42
Dec. 7 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 2 .78
Dec. 14 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ 1 .42
Dec. 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 28 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Dec. 29-31 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 3 1.83 4 1.59 7 2.43 ------ ------ ------ ------ 71 1.62

--2434--

Chart No. 10
Chart No. 10--Logarithmic scale. Certain cities in the United States. Annual death rates for all causes by weeks during the epidemic period.


TABLE NO. 6--Deaths per 1,000 of population in certain cities of the United States during 25 weeks, from week ended Sept. 14 to Mar. 1, inclusive, influenza and pneumonia (all forms).

City. Deaths from-- Deaths from influenza and pneumonia
(all forms).
Influenza Pneumonia
(all forms)
Number. Number
per 1,000
population.
Total 84,355 56,659 141,014  
Albany 570 178 748 6.6
Atlanta 59 795 854 4.2
Baltimore 1,956 3,006 4,962 7.4
Birmingham 902 278 1,180 6.0
Boston 4,711 1,472 6,183 7.9
Buffalo 2,172 903 3,075 6.5
Cambridge 501 197 698 6.3
Chicago 7,878 5,298 13,176 5.1
Cincinatti 1,897 366 2,263 5.4
Cleveland 3,054 1,351 4,405 5.4
Columbus 726 212 938 4.2
Dayton 527 221 748 5.7
Fall River 766 136 902 7.0
Grand Rapids 96 248 344 2.5
Indianapolis 174 975 1,149 4.0
Jersey City 303 671 974 3.1
Kansas City, Mo. 1,461 766 2,227 7.1
Los Angeles 2,636 557 3,193 5.6
Louisville 150 1,056 1,206 5.0
Lowell 174 521 695 6.4
Memphis 152 655 807 5.2
Milwaukee 339 1,247 1,586 3.5
Minneapolis 1,099 194 1,293 3.4
Nashville 640 254 894 7.5
Newark 1,489 1,086 2,575 6.0
New Haven 914 227 1,141 7.4
New Orleans 2,199 1,114 3,313 8.7
New York 15,449 16,511 31,960 6.1
Oakland 975 259 1,234 5.8
Omaha 955 178 1,133 5.8
Philadelphia 8,807 6,759 15,566 8.8
Pittsburgh 2,545 3,153 5,698 9.6
Providence 1,091 531 1,622 6.2
Richmond 691 304 995 6.2
Rochester 1,002 272 1,274 4.8
St. Louis 2,188 1,425 3,613 4.6
St. Paul 894 197 1,091 4.2
San Francisco 3,192 593 3,785 7.9
Syracuse 833 194 1,027 6.4
Toledo 567 318 885 3.4
Washington, D.C. 2,294 822 3,116 7.8
Worcester 941 286 1,227 7.1

As a rule the intensive period in which the causative agent and secondary invaders infected with great virulence was comparatively short--in most instances from one to two weeks--after which milder cases apparently less liable to dangerous or fatal complications were encountered.

Charts Nos. 11, 12, 13, and 14 show the numbers of cases and numbers of deaths by days during the primary epidemics at the United States Naval Training Station, Great Lakes, Ill., United States Naval Training Camp, Pelham Bay Park, N.Y., marine barracks, Quantico, Va., and the United States Naval Treaining Camp, Cape May, N.J. The relation between morbidity and mortality curves varied widely at different stations, as indicated by the charts.

The tendency for sporadic cases to appear daily or frequently for some time after the subsidence of the outbreak was very common in all naval districts. As in numerous cities of the United States, there was a tendency in many naval stations toward a secondary or recurrent

--2435--

Chart 11
CHART 11.--Logarithmic scale, United States Naval Training Station, Great Lakes, Ill.: Influenza epidemic; case incidence and deaths by days.

Chart 12
CHART 12.--Logarithmic scale. United States Naval Training Camp, Pelham Bay Park, New York: Influenza epidemic; cases incidence and deaths by days.

--2436--

Chart 13
CHART 13.--Logarithmic scale. United States Marine Barracks, Quantico, Va.: Influenza epidemic; case incidence and deaths by days.

--2437--

outbreak within a few weeks after the principal epidemic had passed. In some instances, particularly in the more fulminating types, the epidemic had two peaks two or three days apart. Daily incidence curves for different stations show considerable variation from one another, and many epidemiological factors were operative to account for this; the more or less widespread occurrence of influenza in epidemic form during the preceding spring months, the varied nature of naval activities at different stations, size and character of the complement, density of population and character of housing, geographical location and the nature of the extra-naval environment. That the last factor was of importance is shown by the general similarity between the epidemic in the naval station and the epidemic in the city constituting its environment, although there were exceptions of course. For example, in New York City the epidemic was delayed in onset and the death rate was lower than in several of the other principal cities. Outbreaks in naval stations in and around Greater New York also came later and were somewhat less severe with regard to attack reates and case-fatality rates than those in stations located in Boston, Philadelphia, Norfolk, Pensacola, New Orleans, and Chicago.

Chart 14
CHART 14.--Logarithmic scale. United States Naval Training Camp, Cape May, N.J.: Influenza epidemic; case incidence and deaths by days.

Epidemics in the fleet.--Epidemics began in the Atlantic (battleship) Fleet about September 15, reaching their peaks in most instances in about 10 days, but outbreaks began on various transports early in September; in five, during the first week of September.

A study of epidemics in ships of the Navy shows that with a very few exceptions the personnel afloat suffered much less during the pandemic than the personnel ashore in spite of the fact that almost all ships of the Navy were much overcrowded and the crews of transports

--2438--

were exposed to epidemic conditions incident to outbreaks of influenza in highly virulent form among troops in transit. As a rule, the epidemic attack rate on board ship was comparatively low, averaging 16.3 per cent for battleships, 11.4 for cruisers, 29.4 for gunboats, 26.2 for submarines and destroyers, 8.8 for transports and 11.7 for miscellaneous vessels.

The U.S.S. Pittsburgh, an armored cruiser, was an exception. She encountered the disease in its most virulent form at Rio de Janeiro just as it was mounting to the peak of one of the worst of municipal epidemics. During the first seven days of the epidemic on board the Pittsburgh 48.7 per cent of the crew were attacked and for the whole period of the epidemic including mild cases which were not formally admitted to the sick list, the epidemic attack rate was approximately 80 per cent. This epidemic began October 7, reached its peak six days later with the admission of 211 cases that day, and subsided abruptly, only 4 cases occurring the next day and but 43 more in the following month and half. Six hundred and forty-seven cases were admitted to the sick list. Of these, 58 or 8.9 per cent died. The U.S.S. Yacona furnished another exception. Of her personnel, 95 in number, 80 or 84 per cent were attacked in the period between November 17 and 29. This was well after epidemics in New England had subsided. The Yacona encountered the disease at New London, Conn.

The relatively low incidence and low epidemic mortality rates among the personnel on board ship are in general agreement with similar epidemiological findings in the Navy for the 1889-90 pandemic.

Statistics relating to epidemics of influenza for certain vessels of the Navy are shown in table 7 which contains data collected by the fleet surgeon, United States Atlantic Fleet.

TABLE NO. 7.--Statistical data relating to epidemics of influenza on board certain vessels of the United States Navy, by classes, during the period Sept. 1 to Dec. 31, 1918.
  Battleships (29). Cruisers (21). Gunboats (8). Submarine and torpedo destroyers (8). Transports (25). Miscel-
laneous (4).
Total complement 32,434 13,926 1,080 1,136 18,686 1,467
Total number of cases:            
     Officers 232 98 19 12 148 8
     Enlisted personnel 5,076 1,488 299 286 1,357 164
Percentage of total complement attacked 16.36 11.4 29.4 26.2 8.05 11.7
Total number of deaths 239 43 6 9 42 5
Epidemic death rate 7.3 3.0 5.5 7.9 2.2 3.4
Case-fatality rate 4.3 2.7 1.8 3.0 2.7 2.9
Total number of cases complicated with pneumonia 405 79 12 24 100 12
Average period of duration of epidemic, days 31.0 31.7 25.6 29.6 32.8 28.0
Total number of sick days due to influenza and influenza-pneumonia 24,614 7,528 452 1,517 8,218 821
Average number of days 4.63 4.74 1.42 5.09 5.46 4.77
Number of admissions:          
     Members of medical corps 20 5 2 1 9 ------
     Members of hospital corps 36 18 7 4 32 ------
Average number of days between beginning and height of epidemic 9.72 10.42 10.75 10.50 10.64 6.75
Percentage of medical corps attacked 28.16 11.11 33.33 33.33 7.43 ------
Percentage of hospital corps attacked 10.55 10.65 46.66 17.39 4.86 ------
Percentage of officers attacked exclusive of medical officers 21.78 21.27 37.77 17.39 18.99 11.93

--2439--

A report submitted by the force medical officer, Cruiser and Transport Force, contains data for a few more transports than are included in the above table. The figures are as follows:

  Number of men. Number of cases of influenza. Percentage attacked. Number of death. Epidemic death rate per 1,000 Case-fatality rate per cent. Number of cases of complicating pneumonia. Percentage of cases complicated by pneumonia.
Transports:                
     Troops 1129,364 11,385 8.80 733 5.66 6.43 1,040 17.9
     Crew 23,833 2,123 8.88 42 1.75 1.50 141 6.6
1 Includes 5,638 marines.

INFLUENZA STATISTICS, ENTIRE NAVY.

The following tables contain statistics for the entire Navy:

Table No. 8 shows admissions and annual admission rates per 1,000 of complement by weeks, for influenza, pneumonia (all forms), bronchitis and all these causes combined, for the entire Navy for the whole calendar year 1918.

Table No. 9 shows admissions and annual admission rates per 1,000 of complement by weeks, calendar year, 1918, for influenza, pneumonia (all forms), bronchitis, and these causes combined, for the forces of the United States Navy ashore in the United States.

Table No. 10 shows admissions and annual admission rates per 1,000 of complement by weeks, calendar year, 1918, for influenza, pneumonia (all forms), bronchitis, and these causes combined, for the forces of the United States Navy afloat and expeditionary forces, including marines and expeditionary forces in the Navy in Europe. It has not been possible to secure accurate complement figures separately for the forces afloat and the naval or marine corps forces ashore in Europe.

Table No. 11 shjows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia) and pneumonia (all other forms) for the entire Navy.

Table No. 12 shows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia and pneumonia (all other forms) for the United States naval forces ashore in the United States.

Table No. 13 shows deaths and annual death rates per 1,000 of complement by weeks, calendar year 1918, for influenza (including influenzal pneumonia) and pneumonia (all other forms) for the United States naval forces afloat and the expeditionary forces of the Navy, including marines, combined. It has not been possible to secure accurate complement figures separately for the forces afloat and naval or Marine Corps forces ashore in Europe.

Chart No. 15 shows the incidence and prevalence of influenza and death rates by weeks in the Navy during the whole calendar year 1918. As indicated, the death rate from influenza (including influenzal pneumonia), expressed in terms of an annual rate per 1,000 of complement, did not rise above 1 in any week until the week ending

--2440--

September 6, when it was 2 for the force ashore. The curves indicating admission rates show clearly the prevalence of influenza in the spring months not only among the naval forces afloat and in Europe but also among those in the United States. Diminished prevalence among all forces in July and August is very noticeable.

Chart 15
CHART 15.--Logarithmic scale. United States Navy: Annual admission rates and annual death rates per 1,000 of complement, by weeks, calendar year 1918; influenza, including influenzal pneumonia.

Chart No. 16 shows annual death rates per 1,000 of complement by weeks, calendar year 1918, for pneumonia (all forms including influenzal pneumonia) for the entire Navy and separately for the forces ashore in the United States and all other forces, afloat, ashore at foreign stations, and expeditionary forces. While the death rate from influenza did not exceed 1 per 1,000 (annual rate) for any week prior to September 1, as indicated by chart No. 15, the combined rates for influenza and pneumonia (all forms) exceeded this figure nearly every week during January, February, March, April, and May, after which the combined rate, entire Navy, did not exceed this figure until the week ending September 7. Even for the forces ashore in the United States the rate for influenza alone did not exceed 1 per 1,000 until the latter date, although the all-pneumonia rate was occasionally higher than 1 during June, July, and August.

It is very likely that at least some of the deaths from pneumonia in cases where influenza was not considered in diagnosis during

--2441--

Chart 16
Chart 16.--Logarithmic scale. United States Navy: Annual death rates per 1,000 of complement, by weeks, calendar year 1918; pneumonia, all forms, including influenzal pneumonia.

--2442--

January, February, March, and April were primarily due to influenza, and that the outbreaks of this disease which occurred in the late winter and spring were by no means so benign as the figures for influenza now obtainable would indicate.

Table No. 14 shows the distribution of influenza cases and specific admission rates per 1,000 living, according to age groups, enlisted personnel of the Navy, by months, during the period September 1 to December 31, 1918.

Table No. 15 contains similar date for pneumonia (all forms).

Chart 17
Chart 17.--Specific admission rates and specific death rates per 1,000 living, for influenza, including influenzal pneumonia, and for pneumonia (all forms other than influenzal pneumonia), according to age groups, enlisted personnel of the Navy, September 1 to December 31, 1918.

Table No. 16 shows the distribution of deaths from influenza, including influenzal penumonia, among age groups and specific death rates per 1,000 living, by months, enlisted personnel of the Navy, during the period September 1 to December 31, 1918.

Table No. 17 shows deaths and specific death rates per 1,000 living, for pneumonia (all forms other than influenzal pneumonia), by months, according to age groups, enlisted personnel of the Navy, during the period September 1 to December 31, 1918.

Table No. 18 shows case-fatality rates for influenza, including influenzal pneumonia and pneumonia (all other forms), according to age groups.

Admission rates and death rates for several age groups, enlisted personnel, period September 1 to December 31, 1918, are shown in chart No. 17.

--2443--

TABLE No. 8.--Entire Navy: Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Bronchitis. Total
Case. Rate. Case. Rate. Case. Rate. Case. Rate.
Jan. 5 329,878 502 79.04 105 16.12 276 43.16 883 138.84
Jan. 12 336,567 634 97.76 159 24.44 336 51.48 1,129 174.20
Jan. 19 343,256 607 91.52 174 26.00 299 45.24 1,080 163.28
Jan. 26 349,945 680 100.88 146 21.32 273 40.56 1,099 163.28
Feb. 2 356,634 648 94.12 135 19.24 312 45.24 1,095 159.64
Feb. 9 363,323 903 128.96 136 19.24 259 36.92 1,298 185.64
Feb. 16 370,012 815 114.40 112 15.60 319 44.72 1,246 174.72
Feb. 23 376,701 968 133.12 123 16.64 232 31.72 1,323 182.52
Mar. 2 383,390 1,473 199.68 193 26.00 259 34.84 1,925 260.52
Mar. 9 390,079 1,402 186.68 215 28.60 282 37.44 1,899 252.72
Mar. 16 396,768 1,465 191.88 211 27.56 231 30.16 1,907 249.60
Mar. 23 403,457 1,307 167.96 162 20.80 197 24.96 1,666 214.24
Mar. 30 410,146 1,216 153.92 119 15.08 199 24.96 1,534 194.48
Apr. 6 416,835 1,290 160.68 138 17.16 207 25.48 1,635 203.84
Apr. 13 423,524 1,111 136.24 236 28.60 198 23.92 1,545 189.28
Apr. 20 430,213 1,044 122.20 116 13.52 153 18.20 1,283 154.96
Apr. 27 436,902 649 76.96 93 10.92 173 20.28 915 108.68
May 4 443,591 917 107.12 83 9.36 158 18.20 1,158 135.72
May 11 450,280 848 97.76 84 9.36 160 18.20 1,092 125.84
May 18 456,969 675 76.44 60 6.76 164 18.20 899 101.92
May 25 463,658 531 59.28 54 5.72 166 18.20 751 83.72
June 1 470,347 583 63.96 47 4.58 130 14.04 760 83.72
June 8 477,036 549 59.77 49 5.20 124 13.00 722 78.52
June 15 483,725 640 68.64 35 3.64 140 14.56 815 87.36
June 22 490,414 575 60.84 36 3.64 143 15.08 754 79.56
June 29 497,103 816 85.28 32 3.12 174 18.20 1,022 106.60
July 6 503,792 773 79.56 39 3.64 133 13.52 945 97.24
July 13 510,481 954 96.72 47 4.68 147 14.56 1,148 116.48
July 20 517,170 720 72.28 50 4.68 150 15.08 920 92.04
July 27 523,859 613 60.84 50 4.68 213 20.80 876 86.84
Aug. 3 530,548 623 60.84 35 3.12 197 19.24 855 83.72
Aug. 10 537,237 468 45.24 57 5.20 171 16.12 696 67.08
Aug. 17 543,926 489 46.28 63 5.72 226 21.32 778 74.36
Aug. 24 550,615 528 49.40 43 3.64 264 24.44 835 78.52
Aug. 31 557,304 762 70.72 53 4.68 246 22.88 1,061 98.80
Sept. 7 563,993 1,314 120.64 70 6.24 268 24.44 1,652 151.84
Sept. 14 570,682 5,568 507.00 153 13.52 358 32.24 6,079 553.80
Sept. 21 577,371 17,233 1,551.68 1,016 91.00 337 30.16 18,586 1,673.88
Sept. 28 584,060 16,117 1,434.68 2,112 187.72 529 46.80 18,758 1,669.72
Oct. 5 590,749 13,800 1,214.72 1,863 163.80 523 45.76 16,186 1,424.28
Oct. 12 597,438 9,041 786.76 1,090 94.64 434 37.44 10,565 919.36
Oct. 19 604,127 6,396 550.16 790 67.60 327 28.08 7,513 646.36
Oct. 26 610,816 4,418 375.96 364 30.68 296 24.96 5,078 432.12
Nov. 2 617,505 3,809 320.32 299 24.96 296 24.44 4,404 370.76
Nov. 9 624,205 2,596 215.80 176 14.56 307 25.48 3,079 256.36
Nov. 16 624,205 2,152 178.88 136 10.92 377 31.20 2,665 221.52
Nov. 23 624,205 1,709 141.96 158 13.00 352 29.12 2,219 184.60
Nov. 30 624,205 1,257 104.52 81 6.24 356 29.64 1,694 140.92
Dec. 7 624,205 1,411 117.52 93 7.28 428 35.36 1,932 160.68
Dec. 14 624,205 1,734 144.04 147 11.96 503 41.60 2,384 198.21
Dec. 21 620,000 1,598 133.64 136 10.92 378 31.20 2,112 176.80
Dec. 28 614,000 1,075 91.00 97 7.80 270 22.36 1,442 121.68
Dec. 29-31 614,000 428 84.18 35 6.10 86 17.08 549 108.58
Total 503,792 120,404 238.99 12,306 24.42 13,736 27.26 146,446 290.63

--2444--

TABLE No. 9.--United States Navy forces ashore in the United States Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Bronchitis. Total
Case. Rate. Case. Rate. Case. Rate. Case. Rate.
Jan. 5 106,693 281 136.24 81 39.00 185 89.44 547 265.72
Jan. 12 112,262 361 166.92 121 55.64 236 109.20 718 382.28
Jan. 19 107,978 339 162.76 130 62.40 196 94.12 665 319.80
Jan. 26 104,858 368 182.00 117 57.72 185 91.52 670 331.76
Feb. 2 105,089 364 179.92 102 50.44 223 110.24 689 340.60
Feb. 9 103,168 450 226.72 99 49.40 179 89.96 728 366.60
Feb. 16 100,716 440 226.72 79 40.56 239 123.24 758 391.04
Feb. 23 102,018 441 224.64 90 45.76 165 83.72 696 354.64
Mar. 2 105,232 56- 276.64 144 70.72 169 83.80 873 431.08
Mar. 9 106,648 595 290.16 145 70.72 166 80.60 906 441.48
Mar. 16 111,257 674 314.60 132 61.36 136 63.44 942 439.92
Mar. 23 106,557 591 288.08 99 48.36 128 62.40 818 398.84
Mar. 30 107,821 600 289.12 87 41.60 125 59.80 812 391.56
Apr. 6 110,782 657 307.84 100 46.80 131 61.36 888 416.52
Apr. 13 111,942 616 287.04 196 91.00 115 53.04 927 430.56
Apr. 20 114,400 745 338.52 77 34.84 81 36.40 903 410.28
Apr. 27 118,090 398 175.24 71 31.20 125 54.60 594 261.56
May 4 112,968 377 173.16 51 23.40 84 38.48 512 235.56
May 11 121,246 320 136.76 52 21.84 103 43.68 475 203.32
May 18 122,401 209 88.40 39 16.12 96 40.56 344 146.12
May 25 126,855 216 88.40 33 13.52 102 41.60 351 143.52
June 1 132,434 236 92.56 30 11.44 73 28.60 339 132.60
June 8 139,267 211 78.52 27 9.88 80 29.64 318 118.56
June 15 148,282 240 83.72 16 5.20 100 34.84 356 124.80
June 22 154,248 187 62.92 25 8.32 99 34.28 311 104.52
June 29 159,415 236 76.76 26 8.32 119 38.48 381 123.76
July 6 166,456 295 92.04 28 8.32 82 25.48 405 126.36
July 13 171,215 217 65.52 29 8.32 102 30.68 348 105.56
July 20 175,116 203 59.80 35 9.88 102 30.16 340 100.88
July 27 186,093 157 43.68 32 8.84 149 41.60 338 94.12
Aug. 3 197,643 184 48.36 23 5.72 126 32.76 333 87.36
Aug. 10 206,020 197 49.40 43 10.40 116 29.12 356 89.44
Aug. 17 207,693 206 51.48 50 11.96 159 39.52 415 103.48
Aug. 24 214,019 257 62.40 31 7.28 166 40.04 454 110.24
Aug. 31 216,654 468 112.32 38 8.84 182 43.68 688 164.84
Sept. 7 220,339 869 204.88 44 9.88 188 44.20 1,101 258.48
Sept. 14 234,760 4,458 986.96 117 25.48 248 54.60 4,823 1,068.08
Sept. 21 247,954 14,380 3,015.48 825 172.64 205 42.64 15,410 3,231.28
Sept. 28 255,066 11,851 2,416.96 1,829 370.76 406 82.68 14,086 2,871.44
Oct. 5 254,676 9,776 1,993.68 1,593 325.00 387 78.52 11,7756 2,383.68
Oct. 12 255,421 5,757 1,171.56 878 178.36 295 59.80 6,930 1,410.76
Oct. 19 249,392 3,656 761.80 564 117.52 195 40.56 4,415 920.40
Oct. 26 250,831 2,509 520.00 223 45.76 217 44.72 2,949 611.00
Nov. 2 247,020 2,087 438.88 202 42.12 208 43.68 2,497 525.20
Nov. 9 246,313 1,940 409.24 120 24.96 192 40.04 2,252 475.28
Nov. 16 244,974 1,402 298.48 105 21.84 262 55.12 1,769 375.44
Nov. 23 243,385 1,051 224.12 132 28.08 242 51.48 1,425 304.20
Nov. 30 244,296 789 167.44 63 13.00 241 50.96 1,093 232.44
Dec. 7 245,858 1,052 222.04 66 13.52 317 66.56 1,435 303.16
Dec. 14 238,666 1,154 251.16 120 26.00 337 73.32 1,611 351.00
Dec. 21 239,313 913 197.60 101 21.84 239 51.48 1,253 271.44
Dec. 28 228,427 648 147.16 71 16.12 162 36.40 8881 200.20
Dec. 29-31 218,783 269 148.84 23 12.20 51 28.06 343 190.32
Total 193,818 77,457 399.63 9,554 49.29 9,216 47.54 96,227 496.48

--2445--

TABLE No. 10.--United States Navy forces afloat and expeditionary forces (including marines) combined: Admissions and annual admission rates per 1,000 by weeks, 1918, influenza, pneumonia (all forms), bronchitis.

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Bronchitis. Total
Case. Rate. Case. Rate. Case. Rate. Case. Rate.
Jan. 5 222,895 221 51.48 24 5.20 91 20.80 336 78.00
Jan. 12 224,305 273 62.92 38 8.84 100 22.88 411 95.16
Jan. 19 235,278 268 58.76 44 9.36 103 22.36 415 91.52
Jan. 26 245,087 312 66.04 29 5.72 88 18.20 429 91.00
Feb. 2 251,545 284 58.24 33 6.76 89 18.20 406 83.72
Feb. 9 260,155 453 90.48 37 7.28 80 15.60 570 113.88
Feb. 16 269,296 375 72.28 33 6.24 80 15.08 488 94.12
Feb. 23 274,683 527 99.32 33 5.72 67 12.48 627 118.56
Mar. 2 278,158 913 170.56 49 8.84 90 16.64 1,052 196.56
Mar. 9 283,431 807 147.68 70 13.00 116 20.80 993 182.00
Mar. 16 285,511 791 144.04 75 13.52 95 17.16 961 174.72
Mar. 23 296,900 716 125.32 63 10.92 69 11.96 848 148.20
Mar. 30 302,325 616 105.56 32 5.20 74 12.48 722 123.76
Apr. 6 306,053 633 107.12 38 6.24 76 12.48 747 126.88
Apr. 13 311,582 495 82.16 40 6.24 83 13.52 618 102.96
Apr. 20 315,813 269 44.20 39 6.24 72 11.44 380 62.40
Apr. 27 318,812 251 40.56 22 3.12 48 7.80 321 52.00
May 4 330,623 540 86.32 32 4.68 74 11.44 646 101.40
May 11 329,034 528 85.28 32 4.68 57 8.84 617 97.24
May 18 334,568 466 72.28 21 3.12 68 10.40 555 85.80
May 25 336,803 315 48.36 21 3.12 64 9.88 400 61.26
June 1 337,913 347 53.04 17 2.60 57 8.32 421 64.48
June 8 337,769 338 52.00 22 3.12 44 6.76 404 61.88
June 15 335,443 400 61.88 19 2.60 40 5.72 459 70.72
June 22 336,166 388 59.80 11 1.56 44 6.76 443 68.12
June 29 337,688 530 81.12 6 .88 55 8.32 591 91.00
July 6 337,336 478 73.32 11 1.56 51 7.80 540 83.20
July 13 339,266 737 112.84 18 2.60 45 6.76 800 122.20
July 20 342,054 517 78.52 15 2.08 48 7.28 580 87.88
July 27 337,766 456 70.20 18 2.60 64 9.36 538 82.68
Aug. 3 332,905 439 68.12 12 1.56 71 10.92 522 81.12
Aug. 10 331,217 271 42.12 14 2.08 55 8.32 340 53.04
Aug. 17 336,233 283 43.16 13 1.56 67 9.88 363 55.64
Aug. 24 336,596 271 41.60 12 1.56 98 15.08 387 59.28
Aug. 31 340,650 294 44.72 15 2.08 64 9.36 373 56.68
Sept. 7 343,654 445 67.08 26 3.64 80 11.96 551 83.20
Sept. 14 335,922 1,110 171.60 36 5.20 110 16.64 1,256 193.86
Sept. 21 329,417 2,853 450.32 191 30.16 132 20.80 3,176 501.28
Sept. 28 328,994 4,266 673.92 283 44.72 123 19.24 4,672 738.40
Oct. 5 336,073 4,024 622.44 270 41.60 136 20.80 4,430 685.36
Oct. 12 342,017 3,284 499.20 212 31.72 139 20.80 3,635 552.24
Oct. 19 354,735 2,740 401.44 226 32.76 132 19.24 3,098 453.96
Oct. 26 359,985 1,909 275.60 141 20.28 79 10.92 2,129 307.32
Nov. 2 370,485 1,722 241.28 97 135.52 88 11.96 1,907 267.28
Nov. 9 377,892 656 89.96 56 7.28 115 15.60 827 113.36
Nov. 16 379,231 750 102.44 41 5.20 115 15.60 906 123.76
Nov. 23 380,820 658 89.44 26 3.12 110 14.56 794 108.16
Nov. 30 379,909 468 63.96 18 2.08 115 15.60 601 82.16
Dec. 7 378,347 359 48.88 27 3.64 111 15.08 497 68.12
Dec. 14 385,539 580 78.00 27 3.64 166 22.36 773 104.00
Dec. 21 380,687 685 93.08 35 4.68 139 18.72 859 117.00
Dec. 28 385,573 427 57.20 16 2.08 108 14.56 551 74.36
Dec. 29-31 395,217 159 48.80 12 3.66 35 9.76 206 63.44
Total 309,974 42,947 138.55 2,752 8.87 4,520 14.60 50,219 162.01

--2446--

TABLE No. 11.--Entire Navy: Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Total
Case. Rate. Case. Rate. Case. Rate.
Jan. 5 329,878 ------ ------ 6 0.93 6 0.93
Jan. 12 336,567 1 0.15 18 2.75 19 2.91
Jan. 19 343,256 ------ ------ 21 3.17 21 3.17
Jan. 26 349,945 ------ ------ 13 1.92 13 1.92
Feb. 2 356,634 1 .14 25 3.64 26 3.74
Feb. 9 363,323 ------ ------ 18 2.54 18 2.54
Feb. 16 370,012 ------ ------ 17 2.34 17 2.34
Feb. 23 376,701 ------ ------ 22 3.01 22 3.01
Mar. 2 383,390 1 .13 22 2.96 23 3.06
Mar. 9 390,079 ------ ------ 37 4.88 37 4.88
Mar. 16 396,768 1 .13 50 6.55 51 6.65
Mar. 23 403,457 ------ ------ 40 5.14 40 5.14
Mar. 30 410,146 ------ ------ 39 4.94 39 4.94
Apr. 6 416,835 1 .11 23 2.86 24 2.96
Apr. 13 423,524 ------ ------ 19 2.28 19 2.28
Apr. 20 430,213 2 .23 20 2.39 22 2.65
Apr. 27 436,902 1 .11 22 2.60 23 2.70
May 4 443,951 ------ ------ 9 1.04 9 1.04
May 11 450,280 2 .22 11 1.24 13 1.45
May 18 456,969 ------ ------ 13 1.45 13 1.45
May 25 463,658 1 .10 5 .52 6 .62
June 1 470,347 ------ ------ 7 .72 7 .72
June 8 477,036 1 .10 3 .32 4 .43
June 15 483,725 2 .20 1 .10 3 .32
June 22 490,414 ------ ------ 6 .62 6 .62
June 29 497,103 1 .10 2 .20 3 .31
July 6 503,792 1 .09 2 .20 3 .30
July 13 510,481 ------ ------ 3 .30 3 .30
July 20 517,170 ------ ------ 8 .72 8 .72
July 27 523,859 2 .19 3 .29 5 .49
Aug. 3 530,548 2 .19 1 .09 3 .29
Aug. 10 537,237 ------ ------ 5 .48 5 .48
Aug. 17 543,926 ------ ------ 8 .72 8 .72
Aug. 24 550,615 1 .09 4 .37 5 .46
Aug. 31 557,304 1 .09 3 .27 4 .36
Sept. 7 563,993 9 .78 4 .36 13 1.19
Sept. 14 570,682 38 3.43 12 1.09 50 4.52
Sept. 21 577,371 266 23.92 14 1.24 280 24.96
Sept. 28 584,060 989 87.88 64 5.20 1,053 93.60
Oct. 5 590,749 802 70.20 43 3.74 845 74.36
Oct. 12 597,438 655 56.68 26 2.23 681 58.76
Oct. 19 604,127 478 41.08 21 1.76 499 42.64
Oct. 26 610,816 248 20.80 13 1.09 261 21.84
Nov. 2 617,505 170 14.08 2 .16 172 14.35
Nov. 9 624,205 102 8.32 2 .16 104 8.63
Nov. 16 624,205 80 6.24 3 .24 83 6.76
Nov. 23 624,205 71 5.72 4 .33 75 6.24
Nov. 30 624,205 43 3.53 1 .08 44 3.64
Dec. 7 624,205 33 2.70 11 .88 44 3.64
Dec. 14 624,205 42 3.48 8 .62 50 4.16
Dec. 21 620,000 44 3.64 10 .83 54 4.52
Dec. 28 614,000 50 4.21 4 .32 54 4.52
Dec. 29-31 614,000 16 3.17 1 .19 17 3.29
Total 503,792 4,158 8.25 749 1.48 4,907 9.73

--2447--

TABLE No. 12.--United States naval forces ashore in the United States; Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Total
Case. Rate. Case. Rate. Case. Rate.
Jan. 5 106,983 ------ ------ 4 1.92 4 1.92
Jan. 12 112,262 1 0.46 10 4.62 11 5.04
Jan. 19 107,978 ------ ------ 18 8.32 18 8.32
Jan. 26 104,858 ------ ------ 11 5.40 11 5.40
Feb. 2 105,089 1 .49 23 10.92 24 11.85
Feb. 9 103,168 ------ ------ 13 6.24 13 6.24
Feb. 16 100,716 ------ ------ 7 3.58 7 3.58
Feb. 23 102,018 ------ ------ 19 9.36 19 9.36
Mar. 2 105,232 1 .49 15 7.28 16 7.80
Mar. 9 106,648 ------ ------ 20 9.36 20 9.36
Mar. 16 111,257 ------ ------ 31 14.04 31 14.04
Mar. 23 106,557 ------ ------ 23 10.92 23 10.92
Mar. 30 107,821 ------ ------ 17 7.80 17 7.80
Apr. 6 110,782 ------ ------ 16 7.28 16 7.28
Apr. 13 111,942 ------ ------ 12 5.20 12 5.20
Apr. 20 114,400 ------ ------ 8 3.58 8 3.58
Apr. 27 118,090 1 .43 17 7.28 18 7.80
May 4 112,968 ------ ------ 6 2.75 6 2.75
May 11 121,246 2 .83 7 2.96 9 3.84
May 18 122,401 ------ ------ 8 3.38 8 3.38
May 25 126,855 1 .41 2 .78 3 1.19
June 1 132,434 ------ ------ 5 1.92 5 1.92
June 8 139,267 1 .36 1 .36 2 .72
June 15 148,282 1 .35 1 .34 2 .67
June 22 154,248 ------ ------ 4 1.30 4 1.30
June 29 159,415 ------ ------ ------ ------ ------ ------
July 6 166,456 1 .31 1 .31 2 .62
July 13 171,215 ------ ------ 3 .88 3 .88
July 20 175,116 ------ ------ 4 1.14 4 1.14
July 27 186,093 ------ ------ 1 .27 1 .27
Aug. 3 197,643 ------ ------ 1 .26 1 .26
Aug. 10 206,020 ------ ------ 3 .72 3 .72
Aug. 17 207,693 ------ ------ 6 1.45 6 1.45
Aug. 24 314,019 ------ ------ 3 .72 3 .72
Aug. 31 216,654 ------ ------ 2 .47 2 .47
Sept. 7 220,339 8 1.87 3 .67 11 2.54
Sept. 14 234,760 33 6.76 10 2.18 43 9.36
Sept. 21 247,954 225 46.80 11 2.08 236 48.40
Sept. 28 255,066 841 171.08 39 7.80 880 178.88
Oct. 5 254,676 623 126.88 28 5.20 651 132.60
Oct. 12 255,421 496 100.88 19 3.84 515 104.52
Oct. 19 249,392 313 65.00 19 3.95 332 69.16
Oct. 26 250,831 145 29.64 5 .98 150 30.68
Nov. 2 247,020 97 20.28 2 .41 99 20.80
Nov. 9 246,313 70 14.56 1 .20 71 14.76
Nov. 16 244,974 56 11.44 1 .20 57 11.96
Nov. 23 243,385 54 11.44 3 .62 57 11.96
Nov. 30 244,296 33 6.76 ------ ------ 33 6.76
Dec. 7 245,858 27 5.20 9 1.87 36 7.28
Dec. 14 238,666 33 6.76 5 1.04 38 7.80
Dec. 21 239,313 35 7.28 7 1.50 42 8.84
Dec. 28 228,427 41 8.84 2 .45 43 9.36
Dec. 29-31 218,783 12 6.58 ------ ------ 12 6.58
Total 193,818 3,152 16.26 486 2.57 3,638 18.77

--2448--

TABLE No. 13.--United States naval forces afloat and expeditionary forces (including Marines) combined: Deaths and annual death rates per 1,000 by weeks, 1918, influenza and pneumonia (all forms).

Week. Comple-
ment.
Influenza. Pneumonia
(all forms).
Total
Case. Rate. Case. Rate. Case. Rate.
Jan. 5 222,895 ------ ------ 2 0.46 2 0.46
Jan. 12 224,305 ------ ------ 8 1.82 8 1.82
Jan. 19 235,278 ------ ------ 3 .62 3 .62
Jan. 26 245,087 ------ ------ 2 .41 2 .41
Feb. 2 251,545 ------ ------ 2 .41 2 .41
Feb. 9 260,155 ------ ------ 5 .98 5 .98
Feb. 16 269,296 ------ ------ 10 1.92 10 1.92
Feb. 23 274,683 ------ ------ 3 .52 3 .52
Mar. 2 278,158 ------ ------ 7 1.30 7 1.30
Mar. 9 283,431 ------ ------ 17 3.06 17 3.06
Mar. 16 285,511 1 0.18 19 3.43 20 3.64
Mar. 23 296,900 ------ ------ 17 2.96 17 2.96
Mar. 30 302,325 ------ ------ 22 3.74 22 3.74
Apr. 6 306,053 1 .16 7 1.14 8 1.35
Apr. 13 311,582 ------ ------ 7 1.14 7 1.14
Apr. 20 315,813 2 .32 12 1.92 14 2.28
Apr. 27 318,812 ------ ------ 5 .78 5 .78
May 4 330,623 ------ ----- 3 .46 3 .46
May 11 329,034 ------ ------ 4 .62 4 .62
May 18 334,568 ------ ------ 5 .72 5 .72
May 25 336,803 ------ ------ 3 .45 3 .45
June 1 337,913 ------ ------ 2 .30 2 .30
June 8 337,769 ------ ------ 2 .30 2 .30
June 15 335,443 1 .15 ------ ------ 1 .15
June 22 336,166 ------ ------ 2 .30 2 .30
June 29 337,688 1 .15 2 .30 3 .45
July 6 337,336 ------ ------ 1 .15 1 .15
July 13 339,266 ------ ------ ------ ------ ------ ------
July 20 342,054 ------ ------ 4 .57 4 .57
July 27 337,766 2 .30 2 .30 4 .57
Aug. 3 332,905 2 .31 ------ ------ 2 .31
Aug. 10 331,217 ------ ------ 2 .31 2 .31
Aug. 17 336,233 ------ ------ 2 .30 2 .30
Aug. 24 336,596 1 .15 1 .15 2 .30
Aug. 31 340,650 1 .15 1 .15 2 .30
Sept. 7 343,654 1 .15 1 .15 2 .30
Sept. 14 335,922 5 .72 2 .30 7 1.04
Sept. 21 329,417 41 6.24 3 .47 44 6.76
Sept. 28 328,994 148 22.88 25 3.90 173 27.04
Oct. 5 336,073 179 27.56 15 2.28 194 29.64
Oct. 12 342,017 159 23.92 7 1.04 166 24.96
Oct. 19 354,735 165 23.92 2 .29 167 24.44
Oct. 26 359,985 103 14.56 8 1.14 111 15.60
Nov. 2 370,485 73 9.88 ------ ------ 73 7.88
Nov. 9 377,892 32 4.42 1 .13 33 4.52
Nov. 16 379,231 24 3.27 2 .27 26 3.54
Nov. 23 380,820 17 2.28 ------ ------ 17 2.28
Nov. 30 379,909 10 1.35 1 .13 11 1.45
Dec. 7 378,347 6 .78 2 .27 8 1.09
Dec. 14 385,539 9 1.19 3 .40 12 1.61
Dec. 21 380,687 9 1.19 3 .40 12 1.61
Dec. 28 385,573 9 1.19 2 .26 11 1.45
Dec. 29-31 395,217 4 1.22 1 .30 5 1.46
Total 309,974 1,006 3.24 263 .78 1,269 4.09

--2449--

TABLE NO. 14--United States Navy enlisted personnel: Specific admission rates per 1,000 living, for influenza by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age
group.
Comp-
lement
September. October. November. December. Total.
Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate.
15-19 138,666 6,649 47.94 3,973 28.65 906 6.46 746 5.37 12,274 88.51
20-24 214,880 22,676 105.52 15,290 71.10 2,873 13.37 2,700 12.56 43,539 202.62
25-29 82,574 7,656 92.59 5,907 71.53 1,161 14.06 1,023 12.38 15,747 190.70
30-34 24,858 1,859 74.78 1,634 65.73 342 13.75 275 11.06 4,110 165.33
35-39 7,700 220 28.57 228 29.61 53 6.88 60 7.79 561 72.85
40-44 3,422 84 24.54 81 23.67 25 7.30 25 7.30 215 62.82
45-49 1,477 29 19.63 45 30.46 11 7.44 20 13.54 105 7.19
50-54 749 15 20.02 13 17.35 3 4.00 7 9.34 38 50.73
55-59 287 3 10.45 6 20.90 2 6.96 6 20.90 17 59.23
60-64 137 3 21.89 3 21.89 ------ ------ ------ ------ 6 43.06
65-69 19 3 157.36 ------ ------ ------ ------ ------ ------ 3 157.89
70-74 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
75-79 10 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 474,800 39,197 8.41 27,180 57.24 5,376 11.32 4,862 10.24 76,615 161.36

TABLE NO. 15--United States Navy enlisted personnel: Specific admission rates per 1,000 living, for pneumonia (all forms) by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age
group.
Comp-
lement
September. October. November. December. Total.
Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate.
15-19 138,666 524 3.77 436 3.14 69 0.49 73 0.52 1,102 7.87
20-24 214,880 1,952 9.08 1,792 8.33 220 1.02 226 1.05 4,190 19.49
25-29 82,574 777 9.40 792 9.59 121 1.46 84 1.01 1,774 21.48
30-34 24,858 165 6.63 222 8.93 31 1.24 27 1.08 445 17.90
35-39 7,700 22 2.84 28 3.63 8 1.03 4 .51 62 8.05
40-44 3,422 11 3.21 3 .87 ------ ------ 2 .58 16 4.67
45-49 1,477 2 1.35 ------ 1 .67 ------ ------ 3 8.80
50-54 749 1 1.33 ------ ------ ------ ------ ------ ------ 1 1.33
55-59 287 ------ ------ 2 6.96 ------ ------ ------ ------ 2 6.96
60-64 137 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
65-69 19 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
70-74 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
75-79 10 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 474,800 3,454 7.27 3,275 6.89 450 .94 416 .87 7,595 15.99

TABLE NO. 16--United States Navy enlisted personnel: Specific death rates per 1,000 living, for influenza, including influenzal pneumonia, by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age
group.
Comp-
lement
September. October. November. December. Total.
Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate.
15-19 138,666 175 1.26 212 1.52 24 0.17 17 0.12 428 3.08
20-24 214,880 774 3.60 941 4.37 94 .43 74 .34 1,883 8.76
25-29 82,574 336 4.06 472 5.71 59 .71 35 .42 902 10.92
30-34 24,858 93 3.74 136 5.47 13 .52 13 .52 255 10.25
35-39 7,700 10 1.29 15 1.94 4 .51 4 .51 33 4.28
40-44 3,422 3 .87 ------ ------ ------ ------ ------ ------ 3 .87
45-49 1,477 2 1.35 2 1.35 ------ ------ ------ ------ 4 2.70
50-54 749 ------ ------ ------ ------ 1 1.33 ------ ------ 1 1.33
55-59 287 ------ ------ 1 3.48 ------ ------ ------ ------ 1 3.48
60-64 137 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
65-69 19 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
70-74 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
75-79 10 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 474,800 1,393 2.93 1,779 3.77 195 .41 143 .30 3,510 7.39

--2450--

TABLE NO. 17--United States Navy enlisted personnel: Specific death rates per 1,000 living, for pneumonia (all forms other than influenzal pneumonia) by months according to age groups, Sept. 1 to Dec. 31, 1918.

Age
group.
Comp-
lement
September. October. November. December. Total.
Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate. Admis-
sions
Rate.
15-19 138,666 7 0.05 11 0.07 1 0.007 3 0.02 22 0.15
20-24 214,880 47 .21 40 .18 6 .02 17 .02 110 .51
25-29 82,574 28 .33 10 .12 ------ ------ 3 .09 46 .55
30-34 24,858 4 .16 13 .52 1 .04 2 .08 20 .80
35-39 7,700 3 .38 2 .25 1 .04 2 .08 20 .80
40-44 3,422 2 .58 ------ ------ ------ ------ ------ ------ 2 .58
45-49 1,477 1 .67 1 .67 ------ ------ ------ ------ 2 1.35
50-54 749 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
55-59 287 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
60-64 137 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
65-69 19 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
70-74 21 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
75-79 10 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
Total 474,800 92 .19 77 .16 8 .016 30 .063 207 .43

TABLE NO. 18--Case-fatality rates for influenza including influenzal pneumonia and pneumonia (all forms other than influenzal pneumonia) according to age groups, enlisted personnel of the Navy, by months, Sept. 1 to Dec. 31, 1918.

Age
group.
Influenza, deaths per 100 cases. Pneumonia (all forms), deaths per 100 cases.
Sept. Oct. Nov. Dec. Entire
quarter.
Sept. Oct. Nov. Dec. Entire
quarter.
15-19 2.63 5.33 2.64 2.27 3.48 1.33 2.52 1.44 4.10 1.99
20-24 3.41 6.15 3.27 2.74 4.32 2.40 2.57 2.72 7.52 2.62
25-29 4.38 7.99 5.08 3.42 5.72 3.60 1.26 ------ 9.52 2.59
30-34 5.00 8.32 3.80 4.72 6.20 2.42 5.85 3.22 7.40 4.49
35-39 4.54 6.57 7.54 6.66 5.88 13.63 7.14 ------ ------ 8.06
40-44 3.57 ------ ------ ------ 1.39 18.18 ------ ------ ------ 12.50
45-49 6.89 4.44 ------ ------ 3.80 50.00 ------ ------ ------ 66.66
50-54 ------ ------ 33.33 ------ 2.63 ------ ------ ------ ------ ------
55-59 ------ 16.66 ------ ------ 5.88 ------ ------ ------ ------ ------
60-64 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
65-69 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
70-74 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------
75-79 ------ ------ ------ ------ ------ ------ ------ ------ ------ ------

Severity of Influenza During the Autumn Epidemics.

While influenza manifested itself in all degrees of severity from the very mild to the overwhelming types of infection wherever epidemics occurred in the Navy during the autumn of 1918, the outstanding feature everywhere, ashore and afloat, was the frequency with which pneumonia of extremely virulent type complicated the disease. Competent pathologists in various parts of the United States have agreed that the pulmonary lesions did not conform to any of the well recognized types of pneumonia.

Different observers in the Navy have reported that it was difficult or impossible at times to say whether pneumonia was present or not during life and it was impossible in many instances to obtain accurate

--2451--

figures relative to the percentages of cases complicated with pneumonia. For this reason, in many instances, only approximately correct case-fatality rates could be determined for pneumonia.

Pneumonia as a complication of influenza at various stations.-- The percentages of influenza cases complicated by pneumonia and case-fatality rates for influenzal pneumonia at various stations are shown in the following table. The figures relate to all cases of influenza occurring at each station, including those transferred to hospital.

Station. Complement. Percentage of
influenza cases
complicated by
pneumonia.
Case-fatality
rate for
influenzal
pneumonia.
Training station, Newport, R.I. 9,493 18.0 26.0
Training camp, Pelham Bay Park, N.Y.:         
     Primary epidemic, September-October 14,220 18.0   26.0  
     Recurrent epidemic, December 14,220 17.5   25.0  
Training station, Hampton Roads, Va. 11,104 12.2   33.5  
Receiving ship, Norfolk, Va. 7,994 15.3   39.18
Training camp, Charleston, S.C. 4,167 5.6   29.0  
Marine barracks, Parris Island, S.C. 10,424 21.0   15.0  
Training camp, Gulfport, Miss. 1,772 11.4   19.04
Training station, Great Lakes, Ill. 44,605 18.19 48.0  
Navy Yard, Mare Island, Cal. 7,657 14.3   24.8  
Fifth naval district ------ 13.16 35.8  
U.S.S. Pittsburgh ------ 11.0   50.9  

Pneumonia as a complication of influenza in hospital cases.--The percentages of pneumonic complications among influenza cases transferred to hospital and case-fatality rates for pneumonia in such cases varied considerably, as shown in the following table:

Hospital. Percentage
of influenza
cases complicated
by pneumonia.
Case-
fatality
rate for
influenzal
pneumonia.
Naval hospital No. 5, Brest, France:    
     Among patients received from organizations in France ------ 38.0
     Among patients received from transports ------ 48.0
Naval hospital, Cape May, N.J. 55.0 24.0
Naval hospital, Key West, Fla. 22.5 16.3
Naval hospital, Norfolk, Va. 30.0 28.6
Naval hospital, Pensacola, Fla. 8.2 27.2
Naval hospital, Philadelphia, Pa. 24.4 47.5
Naval hospital, Portsmouth, N.H. 38.2 32.3
Naval hospital, Washington, D.C. 27.4 19.7

Epidemiological study of influenza for an entire naval district.--Influenza statistics vary considerably for the different individual stations within a naval district. The following analysis of data from the third naval district illustrates this:

--2452--

Principal stations, third naval district. Station
comple-
ment.
Cases,
influenza.
Deaths,
influenza
and
pneumonia.
Case
incidence
(per cent).
Case-
fatality
rate
(per cent).
Epidemic
death
rate per
1,000
influenza
and
pneumonia.
Air station, Bayshore, N.Y. 880 97 6 11.02 6.18 6.81
Air station, Montauk, N.Y. 270 2 1 .74 50.00 3.70
Air station, Rockaway, N.Y. 843 80 6 9.49 7.50 7.11
Ammunition depot, Iona Island, N.Y. 385 53 1 13.25 1.88 2.59
Armed draft detail, New York 2,750 554 21 20.14 3.80 7.63
District section headquarters, Bath Beach, N.Y. 1,260 310 5 24.60 1.61 3.96
District section headquarters, New Haven, Conn. 436 171 3 39.20 1.75 6.88
Federal rendezvous, Brooklyn, N.Y. 1,700 172 7 10.11 4.07 4.11
Receiving ship at New York 5,800 1,049 48 18.08 4.57 8.27
Rifle range, Caldwell, N.J. 752 165 6 21.86 3.64 7.97
Rifle range, Peekskill, N.Y. 750 215 7 28.66 3.25 9.33
Pelham training camp, New York 15,316 2,616 134 17.08 5.12 8.74
Officer material school, Pelham Bay Park, N.Y. 1,111 69 4 6.21 5.80 3.60
U.S.S. Granite State, New York 566 175 2 30.92 1.14 3.53
Totals and averages 32,819 5,728 249 17.45 4.35 7.58
 





New York City:            
     Age 15-25--Males and females 1,240,510 ------ 3,657 ------ ------ 2.94
     Age 25-45--Males and females 1,987,700 ------ 9,999 ------ ------ 5.03

It is to be noted that low case-fatality rates usually coincide with high case-incidence rates and it might be inferred that some stations reported more mild cases of influenza than others. The large and busy stations reported lower case-incidence rates and higher case-fatality rates than the smaller stations. The epidemic death rates for the various stations show greater uniformity.

Outbreaks of influenza presumably occurred simultaneously among civilians and naval personnel in and about greater New Yorik but, whereas the periods of greatest prevalence had passed in some of the naval stations before October 9, the crest of the epidemic in New York City was not reached until October 26. Among those of the naval personnel quartered outside of naval stations or living under conditions which were essentially civilian the incidence followed that of the civil community. This was particularly the case among the personnel of the steam engineering school, Hoboken, N.J., in the navy yard and among the force attached to district headquarters or employed in various offices.

It is not surprising that the epidemic should have run its course in congested stations more rapidly than among civilians. The epidemic reached its peak in the receiving ship September 21 and in City Park Barracks, October 1. These were the two most congested stations. With regard to preventive measures, quarantine was not imposed nor was the general use of masks or prophylactic sprays advised. Stations remote from cities were advised to prohibit city liberty, but stations in New York were advised by the medical aid to the commandant of the district to relieve congested barracks by freely granting liberty. Special preventive measures, which varied greatly in character, were instituted at different stations upon the initiative of the various medical officers.

At the three air stations gauze masks were worn. It will be noted that the epidemic death rates were moderately high at two of them

--2453--

and low at the United States Naval Air Station, Montauk. An epidemic of influenza occurred at that station in March, 1918, when 48 cases developed during a period of 12 days among the crew, then numbering 119. However, considerable change in personnel had taken place in the meantime, only 20 of those were actually attacked in March remaining.

At the receiving ship in New York, in City Park Barracks, at the Federal rendezvous, and at Bath Beach, all of which stations are in New York City, no restrictions were imposed on liberty; masks were not worn and no other personal prophylactic measures were undertaken. At the United States Naval Training Camp, Pelham Bay Park, liberty was restricted and visitors were excluded. This was also the rule on board the Granite State.

Some of the vagaries of epidemics become apparent when the case incidence and case-fatality rates of the training camp in Pelham Bay Park are compared with those of the Federal rendezvous. The former, located at the extreme edge of the city limits, had its men billeted in many rooms of moderate size and imposed a modified quarantine. At the latter, all men were quartered in one very large room and no restriction was imposed on liberty. The building is an armory located in a thickly populated section of Brooklyn. Pelham suffered more than the Federal rendezvous or the station at bath Beach. It is difficult also to explain the differences in rates at Peekskill and Iona Island. These stations are located opposite each other on the Hudson River, 40 miles above New York. The same restrictions were imposed on liberty at both, and presumably each had about the same amount of communication with the city, but they gave respectively the highest and lowest epidemic death rates. One hundred men of the United States Naval Aviation Detail, Keyport, N.J., escaped without a case, although the neighboring city suffered.

Epidemiological studies among personnel of the Navy Department, Washington, D.C.--The figures for the personnel on duty at the Navy Department, Washington, D.C., furnish a means of judging the effects of epidemic influenza among adults living under civilian conditions.

Bureau. Comple-
ment.
Number
of cases.
Number
of deaths.
Case
incidence
(per cent).
Case-
fatality
rate.
Death rate
per 1,000
for epidemic.
Ordnance 303 37 1 12.2 2.70   3.30
Construction and repair 608 90 2 14.3 2.22   3.28
Steam Engineering 583 89 2 15.2 2.24   3.43
Navigation 1,351 431 5 31.9 1.16   3.70
Secretary's office
Chief clerk's office
98 11 0 11.2 ------ ------
Yards and Docks 635 128 2 20.1 1.48   3.14
Compensation Board 41 4 0 9.7 ------ ------
Judge Advocate's office 46 7 0 15.2 ------ ------
Solicitor's office 35 5 0 14.2 ------ ------
General Board 13 3 0 23.0 ------ ------
Supplies and Accounts 1,699 388 8 22.8 2.06   4.70
Medicine and Surgery 150 35 0 23.3 ------ ------
Marine offices (annex and Corcoran Courts) 566 78 0 13.8 ------ ------
Hydrographic offices 163 26 1 15.9 3.84   6.13
Operations (including O.N.I. inspections and survey) 1,170 243 2 20.8 .082 1.70
Total 7,461 1,575 23 21.0 1.46   3.08
Washington, D.C. 1500,000 25,729 21,658 ------ ------ 3.03

1 Estimated.           2 From Sept. 21 to Nov. 15, 1918.

--2454--

As far as the Navy Department was concerned it may be said that the epidemic ended about November 4, although sporadic cases continued to occur. The case-incidence rate, 21 per cent, coincides very closely with that which appears to have prevailed among civilians in various urban communities where morbidity reports were more or less satisfactory and complete.

Overcrowding in offices appears to have been a factor in the spread of the disease among the Navy Department personnel. The case-incidence rate was higher in overcrowded rooms and offices than in those more evenly proportioned. That the rates were not higher under the conditions of overcrowding, which then existed, was in a measure due to the favorable weather prevailing which made it possible to keep all windows open and utilize all means of ventilation. Of course, all preventive measures that were practicable were put into effect, and a sanitation officer made daily visits to all offices for the purpose of survey and to give practical advice. Not only was more complete sanitary supervision exercised but it is fair to say that those who became ill were able to secure medical advice and care more promptly and more regularly than persons under similar circumstances in civil employment in most of the large cities of the country. It should be stated that a great majority of the persons represented by these dat belonged to the age group 20-30, the age group which practically everywhere showed very high incidence rates for influenza and the highest case-fatality rates.

True case-fatality rates for influenza and influenzal pneumonia, entire Navy.--From August 31 to December 31, 1918, there were reported for the entire Navy 91,656 cases of influenza, 6,425 cases of bronchitis, and 8.816 cases of pneumonia (all forms).

The great majority of all cases of pneumonia in the Navy during this period were influenzal in origin and, if it be assumed that all cases were influenzal, these figures would indicate that 9.6 per cent of the cases of influenza were complicated with pneumonia, of no cases diagnosed as acute bronchitis are included, and 8.9 per cent if the 6,425 cases of bronchitis are included. Furthermore, the case-fatality rate for pneumonia as indicated by these figures would be 49.67 per cent. This is obviously much higher than the true rate, but the true rate can not be determined accurately. There is no doubt about the deaths, but it is known that many cases of pneumonia terminating in recovery were not recognized, and in some cases of influenza which resulted in recovery the diagnosis was not changed to pneumonia even though clinical findings suggested or indicated pulmonic complications. In other words, many nonfatal cases of pneumonia were not reported as pneumonia. Every certificate of death received in the bureau was edited by the Division of Preventive Medicine, and in every case of pneumonia where an influenzal origin was indicated or suggested in the history of the case as contained in the body of the report, the death was charged to "influenzal pneumonia."

During the period, August 31, to December 31, 1918, 4,136 deaths from influenza and influenzal pneumonia occurred in the Navy, and the mean strength was 569.470, making the death rate from influenza 7.26 per 1,000, and the case-fatality rate for influenza 4.5 per cent. The latter rate is undoubtedly higher than the true rate because many mild cases of influenza, and sometimes cases of moderate severity, were not admitted to the sick list. It has been estimated at various

--2455--

stations that for every 100 cases of influenza formally admitted to the sick list, from 50 to 75 mild cases were never recorded. With 50 per cent added to the number of recorded cases of influenza the indicated case-fatality rate becomes 3.0 per cent. This figure more closely approximates the true case-fatality rate than 4.5 per cent. In all probability the true case-fatality rate for influenza in the Navy was between 2.5 and 3.5 per cent.

It is more difficult to reach a conclusion with regard to the case-fatality rate for influenzal pneumonia. The figures given above would indicate that pneumonia was a complication in 9.6 per cent of the cases of influenza. This figure is too low but there are no means of accurately determining the true percentage. At various stations where careful study was possible the figures varied from 11.4 to 21 per cent, giving an average of 15.9 per cent and a median figure of 16.25 per cent. Assuming that approximately 15 per cent of recorded cases of influenza in the navy were complicated with pneumonia the indicated case-fatality rate for influenzal pneumonia during the period August 31 to December 31, 1918, would be 30 per cent, or, assuming that all deaths from pneumonia during this period were really due to influenza, 31.8 per cent.

Recognition of Influenza

Influenza is not easily differentiated from other acute respiratory infections when the disease is not epidemic, and for this reason in studying influenza, distinctions must not be drawn too finely between the types of cases occurring during epidemics, and the types reported as influenza before and after epidemics. A sudden onset with malaise and weakness, leading in a few hours to prostration out of proportion to the other clinical manifestations; the prominence of headache, particularly the so-called post-orbital headache; muscular pains, sharp rise in temperature to 101 or 102 degrees of even higher, and leukopenia, appear to be the principal guides to recognition of the true case of influenza, pending agreement as to the value of bacteriological findings or the discovery of a microöganism which can be agreed upon as the causative agent of the disease.

Studies of cases occurring in various outbreaks of influenza in the Navy during this pandemic show a remarkable similarity in the clinical characteristics of the disease all over the world. Inasmuch as epidemics varied considerably in duration and intensity it is not surprising that there was also considerable variation in the proportion of uncomplicated cases, both mild and severe, to the complicated severe cases. Mild, uncomplicated cases occurred everywhere, even when epidemics were at their peaks, and such cases appear to have had the same characteristics wherever they occurred, before, during, and after the primary epidemic. At the majority of naval stations, as well as on board ship, a certain number of cases occurred which were clinically very severe from the moment of onset and terminated fatally, sometimes in less than 36 hours. These cases occurred principally at the height of an epidemic; were uncommon previous to September 1, 1918, and were not often seen after the passing of the primary epidemic.

The outstanding feature of the pandemic was the frequency with which secondary pneumonia of the bronchial type developed. This

--2456--

complication was the cause of death in practically all fatal cases of influenza.

The clinical course in cases complicated by pneumonia varied considerably at each place or hospital. Pneumonia developed early, almost immediately in some cases; in others only after several days of influenza or after a remission, and in some instances after convalescence had apparently begun.

With due allowance for the fact that a hemolytic streptococcus was associated with most or all cases of complicating pneumonia in one place, whereas a pneumococcus predominated in another place, it may be said that there was a remarkable similarity in the cases complicated with pneumonia as well as in ordinary uncomplicated cases of influenza wherever they occurred, not only in all parts of the United States but in England, France, the West Indies, South America, and the Orient. That is, the general picture of influenzal pneumonia was the same all over the world.

In practically all cases of complicating pneumonia a hemolytic streptococcus, a pneumococcus, the Pfeiffer bacillus, or a combination of these microörganisms seemed to play a part in causing the pneumonic lesions. However, it is generally agreed that the pneumonia cases were sufficiently characteristic to stand out as a type different from cases of ordinary pneumonia seen in recent years and more or less different too from the types of broncho-pneumonia which so frequently complicated measles in 1917 and early in 1918.

From various reports, with reference to clinical and post-mortem findings and with regard to statistical data for various stations and ships in many parts of the world, it appears that of 1,000 cases of influenza from 30 to 40 terminated fatally; from 10 to 30 in some places and as many as 90 or more under unusual circumstances. As a rule, from 100 to 200 cases in a thousand had pneumonia complications with definite clinical manifestations. Such cases averaged, perhaps, 150 per 1,000 cases of influenza. A small number of these patients lived only a day or two, and the exact nature of the infection microörganisms and the immunological conditions involved in such cases are still unknown In many of the fatal cases of pneumonia a secondary invader, a pneumonococcus or streptococcus, or both, seemed to play an important if not the paramount rôle in causing death. In some cases the Pfeiffer bacillus was present in the tissues and in cells in great numbers and appeared to be responsible for the pneumonia, inasmuch as it was recovered in pure culture.

The causes of death other than pneumonia were few. Cerebrospinal fever was a not uncommon concomitant infection or sequela at several training stations and in a few ships.

Besides broncho-pneumonia, the following complications were noted:

--2457--

During the calendar year, 1918, the cause of death in 4,155 fatal cases of influenza was assigned as follows:

Influenza (uncomplicated or complication unrecognized) 931
Pneumonia, bronchial 2,432
Pneumonia, lobar 730
Abscess of kidney 1
Acute dilation of the heart 2
Pulmonary edema 1
Embolism 1
Meningitis, cerebro-spinal 25
Acute nephritis 5
Pleurisy, serofibrinous 2
Pleurisy, suppurative 17
Sinusitis 1
Septicemia 5
Hydropneumothorax 1
Erysipelas      1
     Total 4,155

Of the cases of influenza in which complications did not develop--800 to 875 in a thousand, and probably more than 900 is some instances if the truth could be known--the majority were ordinary cases of influenza, similar to the grippe cases of ordinary times. In some of the uncomplicated cases the patient appeared to be very ill for three or four days. On the other hand, there were always numerous mild attacks which either did not prevent the performance of usual tasks or necessitated confinement to bed or quarters for only one, two, or three days. The frequency with which very mild cases were seen leads to the belief that a great many persons were attacked by the disease in such mild form that it was not recognized even as an acute minor respiratory affection.

It is not improbable that approximately 40 per cent of the total naval personnel actually became infected at some time or other in 1918, which would correspond to the figure accepted for the incidence in civilian populations during the 1889-90 pandemic.

--2458--

Influenzal pneumonia.--Some of the cases were very similar in onset to acute lobar pneumonia, and a good many cases were so diagnosed, particularly early in the epidemic. In some instances even the post mortem findings simulated those of acute lobar pneumonia. The more thoroughly cases were studied the less did it appear that the lesions of influenzal pneumonia were ever those of a true lobar pneumonia.

In most cases the onset of pneumonia was not abrupt, and the pulmonary complication developed so unobtrusively that it was likely to be overlooked without careful and repeated physical examinations. Frequently the temperature, respiration rate, and character of the sputum suggested the presence of pneumonia when it could not be found with the stethoscope. A rising white count was also significant. In some instances the pneumonic complication developed within the first 24 hours, but in the great majority of cases not until after 48 hours, and frequently not until after a remission on the third of fourth day. Several observers noted that broncho-pneumonia of some degree could be considered to exist if there was not a cessation of influenza symptoms by the sixth day.

After full development, the distinguishing features of influenzal pneumonia were extreme toxicity, rapid respiration becoming very marked upon the least exertion, early appearance of cyanosis of the lips, ears and finger tips extending to the body before death; a frequent paucity of physical signs in comparison with the obviously critical condition of the patient, pulmonary edema, and abundant watery bloodstained sputum or thin rusty muco-purulent sputum. Of course, in many cases there were physical signs of extensive involvement of the lungs.

The appearance of the patient; his bluish or purplish lips, cyanosis of the ears, ashen cyanosis of the face or blue mixed with red when there was congestion, drooping eyelids, and the "air hunger" which often seemed due more to toxemia and to changes in the blood than to lack of proper aeration in the lungs, made an unforgettable picture in cases where medical treatment was practically without avail.

Many of the cases were regarded as mixed infections and clinically many were septicemias. In the majority of instances blood cultures were negative, but in some streptococci or pneumococci were obtained from the blood during life. Rarely, the Pfeiffer bacillus was found in blood culture.

Not all cases of influenzal pneumonia presented the picture described above. Indeed, reports from various naval hospitals denote considerable variation in clinical manifestations as well as in post-mortem findings at each place during the epidemic, but this was the picture in many of the cases, especially at the height of the epidemic when influenza seemed to be more highly communicable than before or after and when influenzal pneumonia was more prone to occur. It would not do to compare the pneumonia cases occurring at one place early in the epidemic with those occurring later at another place. Pleurisy of some degree complicated the great majority of pneumonia cases at all stages of the epidemic, but there were very few empyemas until after the epidemic had passed, even in patients living as long as 14 days.

--2459--

Physical signs in the chest varied extremely from those strongly suggestive of frank lobar pneumonia to a few subcrepitant ríles only, elicited with difficultly, or no signs whatever. Collections of fluid, emphysematous areas, collapsed areas, extravasations, filled or obstructed small bronchi, confluent areas of consolidation, alterations of the blood and possibly acute toxic neuritis of the vagus and peripheral nerves of the thorax accounted for diverse physical findings. Frequently neither a diagnosis nor prognosis could be based upon physical findings.

Cases of fatal septicemia were reported in which there was no consolidation in the lungs, although there was intense congestion with extensive bronchitis. The bronchioles and alveoli were filled with a fluid resembling hemolyzed blood. Blood cultures in certain groups of such cases gave pure growths of a green-producing streptococcus which sometimes hemolyzed and sometimes did not. This microörganism also grew as a diplococcus at times and was difficult to distinguish from Type IV pneumococci.

Some observers reported cases of hemorrhagic septicemia without lung involvement other than hemorrhages or extravasations in which a pneumococcus was thought to be responsible. It is possible that this microörganism was really a streptococcus of the type just mentioned.

Morbid anatomy.--At the United States Naval Hospital, Chelsea, Mass., post-mortem study of 23 cases at the height of the epidemic which began in Boston August 27, 1918, showed the Pfeiffer bacillus present in the lungs in pure or mixed culture in 19 cases and in the other 4 a hemolytic streptococcus was present in pure culture. The Pfeiffer bacillus was present alone in 6 of the 23 cases. At the United States Naval Hospital, Philadelphia, lung punctures made in 31 cases during life showed the presence of the Pfeiffer bacillus, predominating or mixed with "strepto-pneumococcus," or with M. cararrhalis and other common microörganisms in 15 cases.

The post-mortem findings in the chest with respect to the amount and character of fluid found in the pleural cavities varied considerably. Pleuritis of some degree occurred in the great majority of all cases of influenzal pneumonia. Thoracentesis was frequently and repeatedly performed during life, necessarily affecting somewhat the amount of fluid found after death, which varied from a few cubic centimeters to a liter or more. In most cases the amount was small.

Reference has already been made to the fact that empyema was of very infrequent occurrence during the epidemic. However, it was found in 6 of 56 cases of influenzal pneumonia coming to necropsy at the United States Naval Hospital, Great Lakes, Ill. In most of the cases of fluid found in the pleural cavities was very thin. It was generally noted that the fluid contained little fibrin and was tinged with blood.

The lesions in the lungs were characteristically those of perio-bronchitis and broncho-pneumonia. When the lesions were limited to one lobe, usually a lower lobe was affected. In most cases areas of consolidation were found in both lungs, and the lesions were scattered through several lobes. In many instances confluent areas of consolidation gave the gross appearances of lobar pneumonia.

--2460--

A striking feature which characterized influenzal pneumonia was the great amount of thin, watery, bloody, or blood-colored fluid or very dark fluid containing hemolyzed blood which dripped from the cut surface of the lung, filled the alveoli and bronchioles, and in the form of extravasations under the visceral layer of the pleura in streaks or in areas of from one to several centimeters in diameter resembled bullae of suggested subpleural hemorrhage.

Many composite pictures were presented, but in general it appears that lung findings could be divided into two principal groups, depending chiefly upon whether death occurred in the first few days of the disease or whether life was prolonged for 10 days or more.

Where death occurred early in the disease the picture was that variously described as acute, hemorrhagic pneumonitis, disseminated hemorrhagic pneumonia, primary toxic injury of pulmonary tissue or rapidly fatal septicemia with intense engorgement and localizations in the lungs. The lungs were heavy. The pleural surfaces were smooth and usually wet, bluish gray, purple, or slate colored, and often showed a mottling or dark red streaks due to collections of hemorrhagic fluid or extravasations of fluid containing blood pigment beneath the pleura. The lung surfaces were usually almost completely free from fibrin. Here and there the lungs were partially collapsed. Various portions of the lungs, especially the lower lobes, showed areas of consolidation, and frequently edema and emphysema were noted in areas not consolidated.

The cut surface of the lung varied in color from bluish gray or grayish purple to dark red. As a rule, affected areas were dark red. Sanguineous red or dark fluid dripped from the cut section. "The coarse nodular consolidation of ordinary broncho-pneumonia was not present." Cases of longer duration frequently showed a greater variety of lesions. "The lungs exhibited a constantly varying picture of broncho-pneumonia from a peppering of discreet lobular areas well scattered throughout all lobes to large and often massive confluent areas of consolidation involving 75 per cent of the lungs." "The shades of color of the prominent lobules surrounded by the red of the unconsolidated areas and the pale collapsed areas gave a mosaic appearance." Areas of emphysema were usually present in uninvolved portions of the lungs as well as in tissue intervening between consolidated areas. Sometimes intense engorgement without real consolidation was found, and from areas filled with fluid and presenting a solidified appearance blood stained or dark fluid exuded upon pressure. The lining membrane of bronchioles was intensely congested and even the lining of the trachea and large bronchi was often deep red.

The relatively small amount of fibrin present in the lung of influenzal pneumonia was noted by most observers. Panbronchitis and peribronchitis were commonly found. The peribronchial and bronchial lymph glands were generally enlarged, intensely inflamed, and often edematous.

In cases of longer duration, coming to necropsy after 10 or more days of illness, more extensive and more complete consolidation was usually found and dilation of bronchioles, congested in the cases of short duration, showed extensive necrosis in the late cases and the bronchi frequently contained thin purulent material or pus.

--2461--

In some of the more prolonged cases diffuse and confluent small abscesses were noted with yellow pus exuding from the cut surface. Fibrino-purulent material was present in many of the late cases. In some instances bronchiectasis was extensive. In general, a prominent feature in the cases of 10 or more days' duration was extensive bronchitis and peribronchitis with foci of broncho-pneumonia in various states from grayish consolidation to abscesses containing creamy pus. In these cases the lungs were dryer but there were traces of previous engorgement. In many instances there were evidences of organization taking place in the alveoli and dilated bronchioles.

In cases coming to necropsy after 14 days of pneumonia inter-lobular fibrino-purulent pleural exudates were not uncommon.

"In sections studied microscopically from the early stage of pneumonia it is more evident than in gross that a general bronchitis and especially bronchiolitis precedes the infiltration of alveoli. One finds in unconsolidated areas, bronchioles filled with an exudate composed of polymorphonuclear and mononuclear leucocytes with varying amounts of fibrin and amorphous hyalin material. The infundibula and air vesicles subtended by the bronchiole may contain an exudate of leucocytes with little or no fibrin, forming a small focus of broncho-pneumonia. More characteristic of this stage of inflammation is a lesion of the walls of certain infundibula and air vesicles in the neighborhood of, and within the latest areas of consolidation. A hyalin membrane partially or completely covers the walls of these air spaces. The membrane is irregular in thickness, sometimes stratified with occasional cells within narrow clefts. It tends to be thickest over the angles of the wall, though it may be so abundant as to fill an alveolus.

"In older foci of pneumonia leucocytes are the predominant inflammatory element, with small amounts of blood and fibrin, but in the diffusely consolidated patches or lobes of short duration, serum, fibrin, and red cells are most conspicuous. Especially prominent are the large areas of hemorrhage from capillary rupture. In certain areas numerous focal necroses of alveolar walls are observed. In older lesions the smaller bronchi contained plugs of leucocytes, fibrin, and hyalin material, and their epithelial lining was partially or completely ulcerated and covered by a fibrino-purulent membrane."

Most of the victims in influenza in the Navy were robust young men when attacked and the numbers of these well-developed and well-nourished bodies at necropsy made a spectacle sad beyond description.

Extreme engorgement of the whole venous system with distension of subcutaneous and abdominal veins filled with a thin black fluid, watery in consistency, was sometimes noted. The right side of the heart was then acutely dilated. Frequently there was no marked alteration in the size of the heart. "The heart muscle commonly had a glazed or scalded appearance." It was noted at times that the pectoral and recti muscles presented the same appearance. Acute degenerative myocarditis was commonly found. Reports made little reference to the condition of the cardiac valves. Acute vegetative endocarditis of the mitral valve was noted in one instance at the United States Naval Hospital, Great Lakes, Ill.

The spleen, liver, and kidneys, as a rule, exhibited varying degrees of congestion. Active acute nephritis was infrequently found. A

--2462--

report from the United States Naval Hospital, Great Lakes, Ill., stated that little or nothing worthy of special note was found in organs other than the lungs in the acute pneumonia cases. Complications were found in cases where death occurred later on, after the primary acute attack had subsided. The spleen was seldom enlarged to any marked degree. It was usually firm. The list of complications given above indicates the character of lesions found in these organs in unusual instances.

In a report from the United States Naval Hospital, Philadelphia, Pa., intense congestion of the adrenal bodies without progressive inflammatory changes was noted. A report from the United States Naval Hospital, Chelsea, Mass., noted small foci of hyalin necrosis in the adrenal bodies in a majority of the cases in which death occurred four or five days after the onset of pneumonia.

First and last, leptomeningitis was found in a good many instances. Sometimes a pneumococcus was recovered from the meninges; sometimes a streptococcus; and rarely, the Pfeiffer bacillus. As previously noted, brain abscesses were occasionally found. Edema of the brain was frequently noted.

Other findings noted in rare instances at post-mortem examination were hyalin degeneration, necrosis, rupture, and hemorrhage into one or both of the abdominal recti muscles, acute arteritis, phlebitis, and septic emboli with resulting infarction of the brain or of one or another of the parenchymatous organs.

Clinical Manifestations of Influenza and Influenzal Pneumonia
as Commented Upon in Various Navy Reports

Headache.--Reports generally agree that headache was one of the most constant symptoms in the early stages of influenza. It occurred as the most prominent symptom in from 75 to 80 per cent of 900 cases of influenza analyzed at the United States Naval Hospital, Philadelphia, Pa., and as the chief complaint in from 50 to 30 per cent of the cases according to whether they were admitted to hospital within the first 24 hours of the disease or not until after 72 hours.

Headache was usually frontal. In many reports it was designated as "post-orbital." The eye balls were frequently painful and tender on pressure. Undoubtedly due to the toxemia in some cases, headache was commonly caused by nasal congestion and rhinitis with blocking of the frontal sinuses.

Headache late in the disease was reported as due to a variety of lesions; inflammation of the frontal sinuses, less commonly other accessory sinuses, neuritis, meningitis, embolism, intracranial congestion and abscess.

Prostration.--Prostration of some degree almost from the moment of the sudden onset of influenza was rarely absent. In cases of ordinary severity the initial weakness was almost always out of proportion to the fever and to the pulse and physical findings in comparison with other acute infectious diseases. Even in very mild cases there was often great weakness which persisted throughout the convalescent period and fatigue was often readily induced long after the patient had returned to duty. Instances were very common where unusually strong, fully developed men perfectly well in the afternoon were so weak the following morning upon admission to hospital with influenza that they could scarcely sit up in chairs.

--2463--

Many patients became ill on the street while on liberty and had not sufficient strength to return to ship or station.

Prostration was commonly attributed to intense early toxemia which occurred suddenly and in complicated cases developed into a profound adynamic state in which myocarditis and toxic neuritis played a part.

Vertigo.--this was an unpleasant symptom frequently present even in mild cases. While brought on by slight exertion it also occurred frequently when the patient was lying quietly in bed.

Chills.--An initial chill was of very frequent occurrence. A definite chill or chilliness occurred in about 50 per cent of the cases. Chilly sensations commonly recurred during the first 24 hours of the disease and not infrequently chilliness recurred at irregular intervals up to 72 hours.

Muscular pains.--Reports from all ships and stations showed uniform agreement in making mention of the prominence of backache and pains of varying severity in other muscle groups and in the joints. A common description was, "The patient feels as though he had been beaten all over with a club." In the Philadelphia series, general muscular pains were noted as a prominent symptom in from 54 to 63 per cent of all cases admitted to hospital.

Coryza.--A "cold in the head" with sneezing and nasal discharge occurred in the early stages of the disease in perhaps half the cases of influenza. In the Philadelphia series this symptom was noted in 20 per cent of the cases admitted to hospital.

Conjunctivitis.--Some degree of congestion of the conjunctivae accompanied coryza. Congestion of the eyes was noted in from 25 to 30 per cent of the 900 hospital cases carefully studied in Philadelphia. Infrequently conjunctivitis of marked degree was noted and corneal ulcers occurred in several instances in a series of 2,924 cases of influenza studied at the United States Naval Hospital, Great Lakes, Ill.

Nausea and vomiting.--The so-called intestinal form of influenza was not common during this pandemic. Nausea occurred in from 10 to 20 per cent of the cases studied at the United States Naval Hospital, Philadelphia, and vomiting occurred in from 5 to 15 per cent. Nausea and vomiting were more common in cases admitted to hospital late in the disease.

In a few cases, perhaps a dozen, diarrhea was associated with nausea and vomiting. In the majority of these instances there was some abdominal distension and pain with tenderness on palpation, particularly in the right iliac fossa. The pain disappeared quickly, as a rule, but simulated appendicitis while it lasted.

A report from the United States Naval Hospital, Chelsea, Mass., noted that nausea and vomiting occurred in a few cases. At the United States Naval Hospital, Great Lakes, Ill., it was believed that nausea and vomiting in the majority of instances were due to overmedication, as these symptoms were relieved by discontinuing medication.

At the United States Navy Base Hospital No. 5, Brest, France, only one case of what might be termed a definite gastro-intestinal form of grippe with nausea and vomiting and severe diarrhea was noted. In a report from the receiving ship at Norfolk, Va., which included a detailed clinical description of 962 cases of influenza, no mention of

--2464--

nausea and vomiting was made, and it is significant that these symptoms were not alluded to in most reports. Diarrhea was not a prominent symptom. In most reports it was not mentioned.

Hematemesis.--Reports indicate that hematemesis occurred very infrequently. It was not mentioned in the report of 2,924 cases at the United States Naval Hospital, Great Lakes, Ill., and in the report from the United States Naval Hospital, Philadelphia, Pa., it is noted that when vomiting occurred the vomitus was usually free from blood. Hematemesis of large amount was not mentioned in any report.

Abdominal distension.--Paralysis of the intestine appears to have preceded death in the majority of fatal cases. Abdominal distension was prone to occur in toxic cases and was difficult to overcome.

Abdominal pain.--Abdominal pain and soreness in the region of the diaphragm were frequently attributed to continued coughing. In some instances degenerative changes in the abdominal muscles were productive of pain. Not infrequently pleuritic pain referred to the region of the gall bladder led to a diagnosis of acute cholecystitis or appendicitis. Occasionally acute cholecystitis did occur.

Hiccough.--Hiccough occurred in approximately 1 per cent of hospital cases. Occasionally it was serious and could not be controlled. Of approximately 3,000 cases of influenza treated in the naval hospital at great Lakes, persistent hiccough occurred in but one instance, the patient dying on the fifth day.

Icterus.--Jaundice occurred infrequently and it is mentioned in only a few reports. It was present, probably, in less than 1 per cent of the cases of influenza. Duodenitis and choledochitis appear to have been rare. Icterus of hematogenous origin occurred occasionally in severe cases and was attributed in a few instances to acute hepatitis. In one case at the United States Naval Hospital, Philadelphia, that of a negro, jaundice was so intense that the sputum was canary yellow in color. Jaundice of some degree was observed in a majority of the fatal cases in the naval hospital at Great Lakes. About 50 per cent of the Philadelphia cases having jaundice terminated fatally.

Nervous system.--In a large majority of influenza cases, even in mild cases, the nervous system was affected to some degree. Insomnia was mentioned in many reports. Somnolence was also frequently noted. Seventy per cent of the hospital cases treated at Great Lakes during the height of the epidemic there exhibited mental apathy. Active delirium occurred in 20 per cent of the cases. Occasionally delirium was active to a maniacal degree. Stupor and lethargy were noted in some instances. Perception was frequently dulled, and often in complicated cases the patient did not realize his serious condition. "Lethargic or mildly stuporous patients with extensive broncho-pneumonia, obviously critically ill and within 24 to 48 hours of death, nevertheless stated that they felt well and requested permission to leave bed and return to duty." On the other hand, marked mental depression was not uncommon in uncomplicated cases of moderate severity and was sometimes associated with a fixed idea that death must follow.

Several observers described cases exhibiting meningeal symptoms; severe headache, stiffness of the neck or retraction of the head and positive Kernig sign with delirium, in which the cerebro-spinal fluid

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was clear. Sometimes lumbar puncture and withdrawal of clear fluid under pressure resulted in prompt alleviation of symptoms.

A mild degree of toxic neuritis of peripheral nerves was not uncommon. Among the sensory phenomena, hyperesthesia, pains in the arms and legs, tingling, itching, heat sensations, and other indications of paresthesia were noted. Sometimes anesthesia followed hyperesthesia. Pain along nerve trunks, notably of the sciatic or median nerve, was complained of in some instances. Various motor nerves were also affected. Some of the fatalities were in part attributed to toxic neuritis of the vagus nerve.

Mental depression not infrequently continued or developed during convalescence from influenza. In the Philadelphia series some post influenzal psychoses were seen. The cases were described as having mild melancholia or suicidal tendencies. One patient had a series of epileptiform convulsions, preceded and followed by melancholia with depressive delusions, from which he ultimately recovered.

Many patients developed neurasthenia during convalescence. Mental depression and loss of interest in the surroundings were noted, and in a number of cases a diagnosis of dementia praecox was made. Recovery usually followed in from 6 to 8 weeks.

Partial paralysis of the palate, ptosis, strabismus, and weakness of various muscles were frequent sequelae even in mild cases of influenza. Impairment of hearing was also observed. Such disabilities usually wore off in the course of a few months.

Temperature, pulse, and respiration.--Many reports agree in the statement that the onset of fever was abrupt. As a rule, the temperature rose rapidly to between 101 and 105 F., and remained high in nearly all cases until a remission occurred on the second, third, or fourth day. In uncomplicated cases the remission usually marked the beginning of convalescence although some cases terminated by lysis, and occasionally a subsequent rise of short duration occurred. A subsequent rise in temperature generally indicated a pulmonary complication, and when the temperature remained high after the sixth day many observers learned by experience to suspect the presence of broncho-pneumonia. In cases of influenzal pneumonia high temperature was the rule--from 104 to 105 F., and frequently higher at certain hours of the day. At the United States Naval Hospital, Puget Sound, Wash., a temperature of 107 F. was observed in one case.

The usual observation was that the pulse was not unduly rapid. Even in pneumonia the rhythm remained regular although it was often momentarily disturbed during a paroxysm of coughing. The pulse was usually soft and the volume large. Frequent mention was made of a poor quality of heart sound at the apex and of muscular impairment. However, cardiac failure per se was not often the immediate cause of death. Many cases were seen in which the apex beat was forcible on palpation and the heart sounds loud and yet the patient was pulseless at the wrist and death was approaching.

Low blood pressure was reported as frequent or constant. The systolic pressure usually ranged from 85 to 110. The diastolic pressure was frequently between 45 and 55. The pulse pressure was often increased.

Many reports indicate that the pulse rate was slow in proportion to the temperature. A pulse of 80 with a temperature of 104° or a

--2466--

pulse of 90 with a temperature of 105° and a respiration rate of 19 or 20 were commonly noted. Exceptionally a very rapid pulse was noted in pneumonia cases. In a few instances bradycardia was observed. A rapid pulse was not uncommon during convalescence from influenza, especially after exertion.

The respiration rate in influenzal pneumonia was not increased to the degree that would be expected from the nature of the lesions in the lungs. The rate was usually below 30. "Whenever the respirations exceeded 24 per minute, pneumonia was suspected, and this suspicion was strengthened if the sputum was bloodstained, excepting when pleuritis caused the increased respiratory rate." Breathing was free but shallow and frequently became very rapid upon exertion. In such cases the form of cyanosis alluded to above appeared to be due, in part at least, to changes in the constituents of the blood leading to air hunger without causing great distress in breathing. With the development of pulmonary edema cyanosis increased, dyspnea became marked, the breathing was rapid, the patient was delirious, and there was great restlessness. "This distressing terminal stage, with the bubbling ríles, frothy sputum, the too vivid picture of heaving chest, cyanosis, and air-hunger facies, will remain as a nightmare of those of us who dealt with these cases in large numbers."

Cough.--Cough was a very constant sign and ranked next after headache in occurrence during the first 48 hours of the disease. There were few cases in which cough did not occur at some stage of the disease. It occurred in from 80 to 85 per cent of all cases of influenza.

Of 352 cases of influenza admitted to the United States Naval Hospital, Philadelphia, Pa., within 24 hours after the onset of the disease, cough was present in 67 per cent and was the chief complaint in 8.5 per cent of the cases thus early in the disease.

Moderate in severity, "dry" or "hacking" at first, and usually accompanied by "tightness" or "soreness" in the chest, the cough loosened rather promptly as a rule and the sputum became abundant. Statements with regard to cough varied considerably in different reports. "Frequently, on the second or third day, patients complained of 'tightness' or 'soreness' of the chest, and there appeared a bronchial cough, moderate in severity, which was productive of large amounts of greenish or whitish mucoid sputum." "Cough developed early in most cases, with definite pain in the chest." The larynx was frequently involved in the course of influenza with resulting laryngeal cough and aphonia. This condition rarely lasted more than a week, and often there seemed to be very little discomfort from that source. During epidemics many persons who did not become acutely ill developed laryngeal or bronchial cough which persisted for several weeks. Few patients actually ill with influenza escaped bronchitis of some degree, and even in mild cases cough was sometimes very distressing and persistent during convalescence. "This persistence of mild bronchitis, with little cough and little or no sputum, should make one careful not to discharge men too early to duty where exposure may precipitate another attack."

With the development of influenzal pneumonia the character of the cough was modified by the nature and extent of the lesions in the lungs and the degree of pleural involvement. Some of the pneumonia patients had very little cough in proportion to the physical

--2467--

findings. When sputum was raised with difficulty the cough was frequently most distressing, paroxysmal in character, and interfered with sleep. When the sputum was abundant it was generally evacuated without difficulty until the patient became too weak to cough effectively, when even with the lungs full there was sometimes no coughing at all.

Sputum.--In uncomplicated cases of influenza the sputum was mucoid at first and later muco-purulent and rather thin, grayish or greenish in color. The amount varied considerably but it was usually moderately abundant after the first two or three days. In exceptional cases there was little or no sputum. In some apparently uncomplicated cases the sputum was rusty or tinged with blood.

In cases of influenzal pneumonia the character of the sputum varied from a thin, watery, bloody fluid resembling diluted red paint, to bloody pus and in later cases and cases of prolonged duration pur greenish or yellowish pus. Destruction of erythrocytes and admixture of free blood pigment with the sputum led to a variety of colors; red, rusty, dark brown, and even black. In some cases the bronchi were filled with fluid; in others the sputum was scanty, but in most cases all through the disease the amount of sputum was more abundant than in ordinary cases of pneumonia. The sputum was frequently recorded as frothy. The more purulent the less froth it contained, as a rule. In the terminal stage with pulmonary edema froth was commonly noted.

Hemoptysis.--As noted above, blood or blood coloring matter in the sputum was of very common occurrence. Actual hemorrhage into the lungs and into the bronchi occurred not infrequently in the pneumonia cases. Undoubtedly hemoptysis was due in many instances to the escape of blood from the intensely congested bronchial mucous membrane. At the United States Naval Hospital, Great Lakes, Ill., it was noted that hemoptysis frequently preceded the development of pneumonia and sometimes continued throughout. All degrees from bloody froth to frank hemorrhage were observed. In reports reaching the bureau no mention was made of fatal pulmonary hemorrhage or of an instance in which death could be attributed to the loss of blood rather than to infection and toxemia.

Epistaxis.--Hemorrhage from the nose was quite commonly associated with influenza in uncomplicated cases as well as with influenzal pneumonia. In Philadelphia, epistaxis occurred in 9.7 per cent of the 900 cases treated in hospital, and in one instance it was necessary to resort to packing and intramuscular injection of serum. Bleeding was frequently due to venous engorgement without evidence of inflammation. The blood seemed to ooze from the mucous membrane and usually no ulceration could be detected. On board the U.S.S. Leviathan epistaxis was observed in 20 per cent of the cases as a very early manifestation of influenza. In the receiving ship at Norfolk, Va., epistaxis was troublesome in 6.2 per cent of the 962 cases of influenza, and it was noted that in every case with intense headache the headache was greatly relieved with bleeding from the nose. Bleeding of some degree was observed in 30 per cent of the 962 cases and, in general, epistaxis bore no relation to the severity of the disease as it occurred in many of the mildest as well as in many of the most severe cases. It is noted in a report from the U.S.S. Northern Pacific that free hemorrhage from the nose occurred

--2468--

in many cases with general improvement in the condition of the patient; so much so that venesection was later practiced in severe cases with good effect. At the United States Naval Training camp, detroit, Mich., hemorrhage from the nose occurred in about 40 per cent of all cases of influenza and in some instances was very profuse. In all cases bleeding was limited to the anterior nares. On board the U.S.S. Wilhemina epistaxis occurred in practically all patients whose symptoms were of moderate severity.

At the United States Naval Hospital, Great Lakes, Ill., acute nasal hemorrhages occurred in a number of cases, apparently with beneficial results. In 9 among 2,924 cases of influenza, epistaxis was sufficiently severe to require packing. Ulcers of the septum were found in four cases.

Tongue and throat.--There was nothing characteristic about the tongue in ordinary influenza cases. In those which were severe or complicated the tongue was usually dry and leathery or it presented a dry beefy red surface covered with glairy mucus.

Sore throat occurred in about 20 per cent of the 900 Philadelphia cases and was the chief complaint in from 3 to 5 per cent. In Norfolk, slight soreness of the throat was a common manifestation. At the height of the epidemic in Boston it was noted that sore throat was not complained of in typical cases. In cases among the naval personnel in France, throat symptoms were few. In the Philippines, sore throat was a prominent symptom in many instances. On the whole, the throat was often congested but usually the patient did not complain of soreness. In the Great Lakes series streptococcus sore throat was occasionally observed. "The patient may or may not have sore throat in the very early stages of influenza--usually not. Not infrequently patients attributed the attack of influenza to a slight sore throat a few days previously, but he majority gave no history of previous illness."

Adenitis.--In a report from the United States Naval Hospital, Philadelphia, Pa., it was noted that a general adenitis was very frequently discovered upon examination. The whole chain of superficial glands was often involved, including the cervical, axillary, epitrochlear, and inguinal glands. Enlargement persisted during the course of the disease, but the glands seldom became larger than a pea or bean.

At the United States Naval Hospital, Great Lakes, Ill., cervical adenitis was seen occasionally and suppuration occurred in four instances among 2,924 hospital cases of influenza.

Blood.--In uncomplicated cases of influenza the leucocyte count was rarely above normal and usually below normal. In fact, a definite leucopenia was a striking feature and a most useful diagnostic sign in influenza all over the world.

The following is a composite blood picture in 100 uncomplicated cases of influenza:

White blood count   6,950
Polymorphonuclear leucocytes per cent 67.5
Small lymphocytes do      21.2
Large lymphocytes do      3.8
Mononuclear leucocytes do      4.4
Transitional cells do      2.1
Eosinophiles do      .7
Basophiles do      .3

--2469--

The following is a composite blood picture in 100 cases of influenzal pneumonia:

White blood count   17,680
Polymorphonuclear leucocytes per cent 82.8
Small lymphocytes do      8.3
Large lymphocytes do      2.1
Mononuclear leucocytes do      2.6
Transitional cells do      3.8
Eosinophiles do      .3
Basophiles do      .1

A report of influenza cases treated in the United States Naval Hospital, Chelsea, Mass., during the height of the primary epidemic states that the average white count was 4,900, but that over half the patients had white counts of less than 3,000 and that the cases in which broncho-pneumonia developed all showed a low blood count.

At the United States Naval Hospital, Puget Sound, Wash., the following findings were obtained in 10 fatal cases of the acute hemorrhagic pneumonitis type attributed to severe streptococcus septicemia complicating influenza.

Case No. Admitted. Died. Average
temperature.
Average
white
count.
1. 24 24 104.0-105.0 (1)
2. 24 26 105.0 4,000
3. 25 27 103.0-105   3,400
4. 25 27 104.0-105   1,500
5. 26 27 104.6-105   3,000-4,000
6. 24 28 104.6-105.6 5,400
7. 24 28 103.0-104   6,800
8. 25 29 105104  104   4,000
9. 29 30 104104  104   4,600
10. 25 30 103.8 3,800

(1) Not taken. Dead two hours after admission.

At the United States Naval Hospital, Great Lakes, Ill., in 571 cases of influenza and influenzal pneumonia blood findings were:

White-blood counts of-- Per cent.
  5,000 or less were found in 15.5
  between 5,000 and 10,000 in 38.3
  between 10,000 and 15,000 in 22.9
  15,000 or over in 24.1

It was noted that counts taken during the height of the acute attack shortly after admission to hospital showed a normal count or a definite leucopenia in practically every case.

A report from the United States Naval Hospital, Philadelphia, Pa., stated that a high or rising white count was maintained in cases of influenzal pneumonia which were progressing favorably, although a falling count, while in general indicating an unfavorable clinical state, seemed not necessarily to define a fatal issue. Many cases with white counts slowly decreasing for several days eventually recovered. An interesting and valuable observation in daily blood examinations was the gradual or sudden change from the blood picture of uncomplicated influenza to that of influenzal pneumonia. By noting the rising white count and reduction in the percentage of small lymphocytes it was frequently possible to anticipate clinical findings of broncho-pneumonia by several days. In a few instances neutrophilic

--2470--

degeneration of polynuclear leucocytes was observed and marked granulation of lymphocytes was noted in one case in a series of over 200 blood examinations.

The following tables show in detail the leucocyte and differential count findings in different series of uncomplicated influenza cases and in different series of influenzal pneumonia cases:

Table No. 19.--Leucocyte counts in 28 early cases of influenza from one war, United States Naval Hospital, Chelsea, Mass., Sept. 1918.

Cases. W.b.c. Poly. Lymph. L. Mono. Trans. Eosin. Baso.
1 6,200 76 20 2 2 ------ ------
2 6,800 25 38 1 5 ------ 1
3 8,400 77 14 3 6 ------ ------
4 10.000 73 25 1 1 ------ ------
5 5,600 44 50 ------ 6 ------ ------
6 6,800 72 24 2 2 ------ ------
7 7,200 80 20 ------ ------ ------ ------
8 7,200 88 12 ------ ------ ------ ------
9 4,400 54 44 2 ------ ------ ------
10 8,000 74 20 4 2 ------ ------
11 6,800 68 30 2 ------ ------ ------
12 6,600 52 45 ------ 2 1 ------
13 4,200 60 40 ------ ------ ------ ------
14 4,600 50 46 2 2 ------ ------
15 5,200 52 46 2 ------ ------ ------
16 5,800 48 52 ------ ------ ------ ------
17 4,200 48 52 ------ ------ ------ ------
18 6,800 64 28 4 2 2 ------
19 7,200 72 26 ------ ------ 2 ------
20 6,800 68 30 ------ 2 ------ ------
21 4,600 66 34 ------ ------ ------ ------
22 5,800 40 56 ------ 4 ------ ------
23 8,600 75 24 ------ ------ 1 ------
24 7,200 78 16 4 2 ------ ------
25 4,400 56 36 4 4 ------ ------
26 4,200 68 32 ------ ------ ------ ------
27 5,000 70 28 2 ------ ------ ------
28 5,400 56 43 ------ 1 ------ ------
Average 6,700 63.7 33.3 1.2 1.2 .21 .035

Table No. 20.--Leucocyte counts in 25 cases of typical influenza, United States Naval Hospital, Philadelphia, Pa., Sept. 26 to Oct. 26, 1918.

W.b.c. Poly-
nuclear.
Small
lymph.
Large
lymph.
Mono-
nuclear.
Trans-
itional.
Eosino-
phile.
Baso-
phile.
5,600 58 36 2 3 1 ------ ------
4,800 65 30 4 1 ------ ------ ------
6,300 68 20 7 3 1 1 ------
8,400 80 15 2 2 1 ------ ------
5,100 77 12 ------ 6 5 ------ ------
8,000 65 15 5 10 5 ------ ------
8,000 77 10 ------ 11 2 ------ ------
6,800 55 28 4 10 2 ------ ------
7,900 58 27 ------ 12 ------ 3 ------
3,500 80 8 6 4 2 ------ ------
6,300 80 20 ------ ------ ------ ------ ------
4,900 71 26 1 ------ 2 ------ ------
7,000 79 12 6 3 ------ ------ ------
8,000 76 15 4 2 3 ------ ------
6,700 61 21 10 7 1 ------ ------
5,800 80 10 5 2 3 ------ ------
3,600 67 23 ------ 7 3 ------ ------
6,500 63 29 ------ 5 3 ------ ------
5,800 77 18 1 3 ------ 1 ------
7,200 71 20 6 ------ 2 ------ 1
6,900 71 19 4 ------ 3 2 1
7,100 73 22 3 1 1 1 ------
5,900 69 22 4 ------ 3 2 ------
6,900 71 19 4 ------ 3 2 1
5,400 65 25 2 6 2 ------ ------

6,336 69.5 19 3 4 2 1.5 1

--2471--

Table No. 21.--Leucocyte counts in 31 cases of influenzal pneumonia from one ward, United States Naval Hospital, Chelsea, Mass., Sept., 1918.

Case. W.b.c. Poly. Lymph. Trans. L. Mono. Baso. Eosin. Temp-
erature
° F.
1 26,200 81 18 1 ------ ------ ------ 104    
2 29,000 89 10 1 ------ ------ ------ 100    
3 14,600 73 26 1 ------ ------ ------ 104    
4 14,600 80 19 ------ ------ 1 ------ 100    
5 13,600 71 24 3 ------ 2 ------ 104    
6 10,000 82 17 1 ------ ------ ------ 99    
7 37,000 75 20 1 2 2 ------ 103    
8 17,600 75 16 4 5 ------ ------ 102    
9 29,900 91 8 1 ------ ------ ------ 100    
10 17,200 78 19 2 1 ------ ------ 103    
11 10,000 78 20 2 ------ ------ ------ 99    
12 7,000 88 10 2 ------ ------ ------ 99    
13 13,000 80 20 ------ ------ ------ ------ 102    
14 17,000 87 10 3 ------ ------ ------ 104    
15 13,600 86 12 ------ 2 ------ ------ 102    
16 28,800 82 14 2 2 ------ ------ 102    
17 4,600 78 19 2 1 ------ ------ 103    
18 14,800 96 4 ------ ------ ------ ------ 104    
19 12,600 70 28 2 ------ ------ ------ 105    
20 12,200 84 16 ------ ------ ------ ------ 103    
21 7,800 67 29 3 1 ------ ------ 101    
22 6,400 66 34 ------ ------ ------ ------ 104    
23 7,400 53 46 1 ------ ------ ------ 101    
24 10,000 56 42 2 ------ ------ ------ 99    
25 3,600 84 16 ------ ------ ------ ------ 104    
26 16,800 60 36 3 ------ ------ 1 99    
27 6,800 56 40 4 ------ ------ ------ 104    
28 9,000 61 36 3 ------ ------ ------ 99.5
29 12,200 82 16 2 ------ ------ ------ 103    
30 15,800 76 22 2 ------ ------ ------ 100    
31 19,400 78 18 2 2 ------ ------ 102    
Average 13,980 76.23 21.45 1.61 .52 .16 .03 101.8

Table No. 22.--Leucocyte counts in 25 cases of influenzal pneumonia, United States Naval Hospital, Philadelphia, Pa., Sept. 26 to Oct. 26, 1918.

W.b.c. Poly-
nuclear.
Small
lymph.
Large
lymph.
Mono-
nuclear.
Trans-
itional.
Eosino-
phile.
Baso-
phile.
22,600 95 2 1 ------ 2 ------ ------
13,600 88 6 1 2 3 ------ ------
12,100 75 3 3 9 6 2 2
16,000 77 13 4 1 3 2 ------
16,500 85 10 ------ 1 4 ------ ------
12,000 89 3 ------ 4 4 ------ ------
15,600 90 1 1 2 6 ------ ------
49,900 86 ------ 1 1 12 ------ ------
69,600 92 2 ------ 1 5 ------ ------
24,300 87 2 2 4 5 ------ ------
22,800 88 12 ------ ------ ------ ------ ------
14,000 86 7 ------ 2 5 ------ ------
20,200 84 3 4 4 5 ------ ------
19,000 91 2 1 1 5 ------ ------
43,000 98 1 ------ 1 ------ ------ ------
25,600 82 10 1 2 5 ------ ------
25,000 82 2 2 9 5 ------ ------
20,900 86 5 ------ 4 5 ------ ------
17,500 77 20 1 1 1 ------ ------
18,900 81 14 ------ 4 1 ------ ------
19,600 78 12 5 1 3 1 ------
15,600 78 10 5 4 2 1 ------
23,800 82 16 ------ ------ 2 ------ ------
13,600 82 17 ------ ------ 1 ------ ------

23,212 85.24 7.04 1.28 2.32 3.8 .24 .08

Urine.--Reports indicate that serious renal complications were very rare. At the United States Naval Hospital, Great Lakes, Ill., albumin was reported present in about 20 per cent of the urines examined.

--2472--

Casts were found only occasionally. Acute nephritis with bloody urine and edema occurred in 7 of 2,924 cases of influenza.

On board the U.S.S. Solace albumin and granular casts were found in the urine in about 10 per cent of the cases treated.

At the United States Naval Hospital, Philadelphia, Pa., in nearly all cases seriously ill the urine contained albumin and occasionally casts, but there was never acute involvement of the kidneys or evidence of serious renal changes. Functional kidney tests made with phenol-sulpho-phthalein were unsatisfactory and did not give any information of importance. There were a number of cases of retention of urine necessitating catheterization a few times. Of 2,130 urines examined, 614, or 28.8 per cent, contained albumin; 204, or 9.6 per cent, pus cells. Casts were present in 192 or 8.6 per cent. Passive congestion of the kidneys was common. The urine was diminished in quantity and usually showed only a trace of albumin, high specific gravity, a few hyalin and granular tube casts, and not infrequently a number of red blood cells. These findings were sometimes interpreted as indicating acute toxic nephritis, but clinically it was impossible to recognize evidence of uremia, the symptoms of which, if present, were merged in the picture of toxemia.

Skin.--Judging from Navy reports, lesions of the skin were neither common nor characteristic. Herpes of the face, erythema, purpuric spots, purpura hemorrhagica and eruptions more or less like those of scarlet fever and measles were mentioned in a few reports.

A report from the United States Naval Hospital, Philadelphia, Pa., states that a papular eruption was observed on the back and, to a lesser extent, on the front of the body in many cases upon admission ito hospital or later during the course of the disease. The papules were frequently capped with minute pustules varying in size from pin point to pinhead.

Urticaria occurred not infrequently in cases where serum was used.

The Incubation Period of Influenza

Numerous reports indicate that the period of incubation was 48 hours or less in cases where the time and place of exposure could be fixed with reasonable certainty. No report furnished evidence that the incubation period was greater than 48 hours but the possibility of longer periods can not be ruled out.

In the receiving ship at Norfolk, Va., (St. Helena), among 962 cases of influenza close observation indicated that the period of incubation varied from a few hours to two days.

At the United States Naval Hospital, Chelsea, Mass., the first cases from the first outbreak in Boston at Commonwealth Pier (the receiving ship), were admitted to hospital on Thursday afternoon, August 29, 1918. Blood counts, blood cultures, and throat cultures were made immediately by laboratory officers, one of whom developed influenza the following Saturday morning, and another medical officer who made the first physical examination was also attacked on Saturday.

While it is barely possible that both of these officers were exposed to a case of influenza several days before August 29 it is more probable that the disease developed from exposure on the latter

--2473--

date. A chief pharmacist at the hospital whose duties had not previously brought him into contact with patients, accompanied an ambulance to Commonwealth Pier on that day and he developed influenza within 24 hours.

In Santiago, Dominican Republic, no case of influenza occurred among marines in barracks there until December 9, although seven cases had been reported among natives by December 5. A quarantine against the town was in force at this time. On December 9 an officer who had contracted influenza in Puerta Plata became ill and was quarantined in his house. On December 11, a mail orderly who had been in contact with this officer became ill but did not report at sick call. Forty-eight hours after the arrival of the mail orderly in barracks, 15 men sleeping in his immediate neighborhood developed influenza. A common drinking cup was in use at the barracks. Another instance where the immediate source of infection could probably be traced relates to the telephone operators. These men stood 4-hour watches. One of them developed influenza and then four others came down in quick succession, each in about 46 hours after the termination of his watch.

At the officer material school, Princeton University, the medical officer had an unusually good opportunity to note the length of the incubation period in a considerable number of cases where the time of exposure could be quite definitely fixed. He concluded that the incubation period was just about 48 hours in practically all cases.

The Causative Agent of Influenza

Those who have engaged in studying the bacteriology of influenza and influenzal pneumonia during the pandemic are almost unanimously agreed that the causative agent has not been discovered. The Pfeiffer bacillus, pneumococci of all types, hemolytic streptococci and green producing streptococci, as well as other microörganisms commonly found in the mouth and in discharges from the respiratory tract--staphylococci, micrococcus catarrhalis, bacillus mucosus and spirochaetes--have been isolated from the sputum and from lesions in the lungs in varying percentages of cases.

Pfeiffer bacillus.--It is unnecessary here to record in detail the frequency with which this microörganism was found. The technique for its isolation in pure culture was not sufficiently understood generally either by bacteriologists in the Navy or in civil life at the height of the autumn epidemics to justify comparisons between the bacteriological findings in different epidemics and in different localities. Some workers who failed to find the Pfeiffer bacillus at first were able to isolate it in practically all cases after they had been set right by those who had adopted a suitable technique. At some naval stations the bacillus was found in practically all cases of influenza--often early in the disease--and was isolated from the lung tissues in from 60 to 80 per cent of fatal cases of influenzal pneumonia. In a considerable percentage of such cases it was the only microörganism recovered. In a few instances it was found in blood cultures taken during life and in cultures from the meninges in cases of complicating meningitis. However, it was not found in all cases even by those who had demonstrated their knowledge of a reliable technique and some epidemics it was either absent or

--2474--

seldom recovered. As described below, experimental attempts to produce the disease signally failed. Studies in immunity gave various results but furnished no evidence that a single strain was being recovered in different epidemics or even from different cases in a local outbreak. The ability to produce agglutinins was variable and frequently with the identical strain no agglutinins could be detected in the serum of patients from whose sputum the bacilli were isolated, even though they were found in large numbers and in phagocytic cells from the lungs. In many instances agglutinins could not be demonstrated in the serum of animals after thorough attempts to immunize them had been made. In instances where a serum would agglutinate its particular strain it not infrequently failed to agglutinate bacilli recovered from another case of influenza in the same local epidemic although agglutination would occur with a serum specific for the latter strain.

Altogether, evidence was furnished for the belief that many strains of the Pfeiffer bacillus were associated with the epidemic but that no strain predominated. It seems clear that the Pfeiffer bacillus as an early secondary invader took an important part in causing the lesions of mixed infection in many cases, as it probably did in the 1889,1890, 1891, and 1892 epidemics.

Pneumococci and streptococci.--No particular type of pneumonococci predominated in different epidemics and frequently the type recovered from pulmonary lesions in fatal cases occurring in the same epidemic varied. In some epidemics, notably those in battleships of the Atlantic Fleet and in stations in the vicinity of Norfolk, Va., pneumococci appeared to predominate as secondary invaders and to be responsible largely for the fatalities. In most epidemics both pneumococci and streptococci were found in cultures from the lungs, and frequently pneumococci of one or more types and streptococci were recovered together from the same case. Sometimes during a prolonged epidemic pneumococci were found in a high percentage of the fatal cases at one stage, and later were found infrequently while streptococci predominated. In other epidemics, notably those among naval organizations at Puget Sound, and in Seattle, Wash., a streptococcus appeared to be responsible almost altogether for the pneumonias. This appeared to be a single strain which tended to grow as a diplococcus and produced a moderate amount of green in cultures. Sometimes it caused hemolysis and sometimes it did not. It might easily have been confused at times with certain strains of Type IV pneumococci. It was probably the same microörganism as the coccus described by Mathers. Satisfactory evidence that there was but a single strain was not furnished.

The general conclusion which might be drawn from investigations carried on in many naval laboratories is that whatever the causative agent of influenza may be and the likelihood that the virus itself was primarily responsible for influenzal pneumonia as well as for the lesions in mild uncomplicated cases, hemolytic streptococci, a strepto-pneumococcus-like microörganism, the Pfeiffer bacillus, and pneumococci of different types were severally and collectively responsible to a large extent for the severity of complications in most of the fatal cases of the disease. It would appear altogether probable that without successful invasion by streptococci or pneumococci,

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the infectivity of which had been greatly heightened under the existing conditions of war, the case-fatality rates associated with the 1918 autumn epidemics would have been no higher than in epidemics occurring during previous pandemics.

As bearing on the heightened virulence of the causative agent of influenza during a primary epidemic, and possible attenuation subsequently, the following study made at the marine barracks, Quantico, Va., is of interest:

Of the men admitted to sick list with a diagnosis of influenza during the first three weeks of the primary epidemic, 4.1 per cent died, while the case-fatality rate for cases admitted during the second three weeks was only 2.6 per cent. In the fifth week of the epidemic there were 3 deaths in 94 cases and these were in men who had recently arrived. In the sixth and seventh weeks 166 cases of influenza were admitted to hospital, with no deaths. Of this number about 100 were men who had recently arrived in good health, but subsequently contracted infection at Quantico.

It might be inferred from these facts that the microörganism which caused the epidemic at Quantico gradually became attenuated and that notwithstanding the introduction of susceptible persons from the outside the case-fatality rate was nil.

During the eighth week after the beginning of the primary epidemic the disease again became prevalent and the case-fatality rate rose suddenly to 6 per cent during the week ending November 4. Investigation showed that a draft of 958 men had arrived from Parris Island, S.C., on October 27, 1918, and that immediately upon arrival 50 cases of influenza were admitted to hospital from this draft.

Many other cases subsequently appeared. The draft may have brought with it a virulent strain of the causative agent which had not yet become attenuated. The following is an attempt to show this in tabular form:

  Week of-- Total
Sept.
9-16.
Sept.
17-23.
Sept.
24-30.
Oct.
1-7.
Oct.
8-14.
Oct.
15-21.
Oct.
22-28.
Oct. 29-
Nov. 4
Nov.
5-11.
Total cases admitted 163 952 714 301 94 36 130 18 268 2,876
Died1 9 34 33 13 3 ------ ------ 13 12 117
Case-fatality rate 5.5 3.6 4.6 4.3 3.2 ------ ------ 6.0 4.4 ------
  4.1 2.6 ------ 5.1 ------
Quantico strain. Parris Island strain. ------
1 A death is charged to the week during which the deceased was admitted to hospital as a patient, although the death may have occurred later.

Modes of Transmission

While it is presumed now, just as it was before the pandemic, that the causative agent of influenza is transmitted from person to person, either directly or indirectly, by moist secretions or fresh discharges from the mouth and nose no proof of this has been forthcoming. It

--2476--

may be assumed that the disease is highly communicable and that it spreads both by direct and indirect contact of healthy persons with patients. It may be that the virus is carried by healthy persons, but this can neither be proved nor disproved at the present time. Many of the cases of influenza are so mild that the infected individual is able to go about his business and is thus capable of spreading the disease.

Just after the crests of the earlier epidemics were reached two series of experiments were authorized by the Navy Department under arrangements made by the Bureau of Medicine and Surgery in cooperation with the United States Public Health Service for the purpose of determining, if possible, the mode of transmission of influenza as well as the causative agent.

Boston experiments.--These experiments were carried on jointly by Lieutenant Commander, M.J. Rosenau, Medical Corps, United States Naval Reserve Force, and Lieutenant W.J. Keegan, Medical Corps, United States Naval Reserve Force, and by Surgeon J. Goldberger and Assistant Surgeon G.C. Lake, United States Public Health service, at the United States Quarantine Station, Gallups Island, Boston, Mass. The subjects of experiment were 68 volunteers from the United States Naval Detention Training Camp, Deer Island, Boston. These volunteers had been exposed in some degree to an epidemic of influenza at the training camp or at some station prior to coming to Deer Island; 47 of the men were without history of an attack of influenza during the recent epidemic, and 39 of these were without history of an attack of such illness at any time during their lives.

The experiments consisted of inoculations with pure cultures of Pfeiffer's bacillus, with secretions from the upper respiratory passages, and with blood from typical cases of influenza. The study was begun November 13 with an experiment in which a suspension of a freshly isolated culture of Pfeiffer's bacillus was instilled into the nose of each of three nonimmunes and into three controls who had a history of an attack in the recent epidemic. None of these volunteers showed any reaction following this inoculation. Another experiment was made at a later date with a suspension of a number of different pure cultures of Pfeiffer's bacillus, of which four were recently isolated. Ten presumably nonimmune volunteers were inoculated with the same negative results.

Three sets of experiments were made with secretions, both unfiltered and filtered, from the upper respiratory tract of typical cases of influenza in the active stage of the disease. In these experiments a total of 30 men were subjected to inoculation by means of spray, swab, or both, of the nose and throat. The interval elapsing between securing secretions from the donors and inoculation of the volunteers was progressively reduced in these experiments, so that in the third of the series the interval at most was 30 seconds. In no instance was an attack of influenza produced in any of the subjects. An experiment was made in which the members of one of the groups of volunteers which had been subjected to inoculation with secretions were exposed to a group of cases of influenza in the active stage of the disease in a manner intended to simulate conditions which in nature are supposed to favor the transmission of the disease. Each of this group of 10 volunteers came into close association for a few

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minutes with each of 10 selected cases of influenza in the wards of the United States Naval Hospital, Chelsea. At the time the volunteers were exposed to this infection the cases were from 10 to 84 hours from the onset of their illness and 4 of them were not over 24 hours after the onset. Each volunteer conversed a few minutes with each of the selected patients, who coughed into the face of each volunteer in turn, so that each volunteer was exposed in this manner to all 10 cases. The total exposure amounted to about three-quarters of an hour for each volunteer. None of these volunteers developed any symptoms of influenza following this experiment.

Advantage was taken of the opportunity for making this study to attempt to confirm the reported positive results of transmission of influenza by Nicolle. Secretions from five typical cases of influenza were secured, filtered, and some of the filtrate inoculated subcutaneously into each of a group of 10 volunteers. At the same time blood was drawn from the same cases and pooled, and some of the mixed blood injected subcutaneously into each of another group of 10 volunteers. The time lost between drawing the blood and inoculating it in no case exceeded three quarters of an hour. None of the men subjected to these inoculations developed any evidences of illness.

In the foregoing experiments the patients serving as donors belonged to groups from epidemic foci either on shipboard or at institutions. The great majority indeed belonged in a group from an epidemic on board the U.S.S. Yacona. Of the personnel of this vessel, 95 in number, 80 or 84 per cent, were stricken with the disease in an epidemic between November 17 and 29.

San Francisco experiments.--The following observations were carried out practically simultaneously with those described above. The work was done at the Angel Island Quarantine Station, San Francisco, Cal., utilizing volunteers from the Yerba Buena Naval Training Station, San Francisco. The experiments were carried on jointly by Surgeon G.W. McCoy of the United States Public Health Service, and Lieutenant De W.G. Richey, Medical Corps, United States Naval Reserve Force. The volunteers who were used in these experiments differed from those used at Boston in two respects--first, the personnel of the Yerba buena staton had not been exposed to influenza in the present epidemic and were therefore presumed not to possess any special natural immunity; second, all of the men had been vaccinated with large doses of a bacterial vaccine containing Pfeiffer's bacilli, the three fixed types of pneumococci and hemolytic streptococci. It is impossible at present to state what influence this vaccination may have had in promoting resistance to influenza infection, but to judge by the results of controlled experiments, elsewhere such vaccinations may for the present purpose be ignored.

Brief details of the experiments are as follows:

Work with cultures.--A group of 10 volunteers was divided into two equal squads. One group had instilled into the nostrils of each man a heavy suspension made by emulsifying cultures of eight strains of Pfeiffer's bacillus without filtration. The other group had the same material used after passage through a Berkefeld N-candle. The results were negative, though the men were held under observation for seven days.

--2478--

Work with secretions.--Four groups of volunteers, of 10 men each, were used for these experiments. Emulsions of secretions from the upper respiratory passages of active cases of influenza from 15 to 48 hours from the onset were instilled into the nose by means of a medicine dropper, or with an atomizer. In each experiment approximately an equal number of volunteers were treated with the same emulsion after filtration through a Berkefeld N-candle. In every case the results were negative, so far as the reproduction of influenza is concerned. The men were all observed for seven days after inoculation. In three cases in which unfiltered material had been instilled sore throat developed which corresponded clinically with acute tonsillitis, and in two of these cases an almost pure culture of a hemolytic streptococcus was secured from throat cultures.

A filtered emulsion of material from the upper air passages of an acute case of influenza was dropped into the conjunctivae of two volunteers and the same material injected subcutaneously into one volunteer. In each case the result was negative.

One cubic centimeter of blood taken during the active stage of influenza was inoculated subcutaneously into one volunteer with negative results.

In all of these experiments the time between the collection of the material from the patient and its inoculation into the volunteers was in the neighborhood of three or four hours. The conditions under which it was necessary to conduct experiments did not permit a shorter interval. The unfiltered suspensions which were used were submitted to cultural examination after inoculation and found to contain living organisms as follows: Pfeiffer's bacillus, pneumonococci of Group IV, and hemolytic streptococci.

Unfortunately, although performed with the utmost care upon a large number of volunteers, none of these experiments furnished any conclusive evidence in spite of the fact that attempts to transfer the disease were made in the freest possible manner. However, the results obtained in these studies certainly seem to invalidate the conclusion reached in previous filtration experiments in which controls had not been thought necessary.

The outstanding facts are that all attempts to transfer the disease from patients ill with influenza in the acute stages, from 10 to 84 hours from the onset of symptoms, failed. The direct exposure of volunteers in the hospital ward, each volunteer to several influenza patients, thus affording opportunity for transmission of the disease by what has been presumed to be the natural and usual method of dissemination, as well as the promptness with which fresh moist secretions were transferred from patient to volunteer, and the precaution to make subcutaneous inoculations with pooled blood and pooled nose-and-throat secretions from patients acutely ill would appear to leave little to be desired in respect to the completeness with which this research work was performed. Further attempts were made later in Boston to secure more conclusive results by obtaining secretions from patients in the very early stages of the disease, but these subsequent experiments led to findings which were scarcely more definite than those described.

Negative as the results of these experiments were the work itself was of the utmost importance and it serves well to check the generally

--2479--

entertained belief that the transmission of an acute communicable disease of the respiratory type is a very simple matter. While the transfer of the causative agent of such a disease from one individual to another may reasonably be assumed to take place commonly by means of the "droplet spray" directly, as well as indirectly, by means of a freshly contaminated article, such as a drinking utensil or by the fingers which have touched a contaminated article, it is nevertheless probable that immunological conditions play a most important part and that the time of exposure has a determining influence as well as the duration of exposure, the immunological state of the patient (aggressiveness of the causative microörganism) and the immunological state of the person exposed. From the results obtained in these efforts to transmit the disease, influenza especially would appear to require particular conditions for its transmission and yet the gross epidemiology of the disease indicates that it is highly communicable and spreads promptly wherever it is introduced.

Practically all persons who have not had influenza appear to be susceptible to an attack although not necessarily a severe one. Perhaps a majority of those who had the disease in previous years experienced an attack in 1918, if not in severe form at least as a transient mild infection. On the other hand, as pointed out above, many persons in the Navy who had influenza in mild form during the spring months escaped an attack in the autumn of 1918, although there were also many exceptions.

It was reported from the U.S.S. Nashville that cases which developed during the autumn epidemic in the United States were even milder than those which occurred during the spring and summer in European waters. All new cases developed in men received on board after returning to the United States. No man who had had the disease in Europe was attacked.

In the Seventh regiment of Marines, stationed at San Juan, Santiago de Cuba, during a recurrent epidemic of influenza it was observed that the Ninety-third Company suffered heavily. During the primary epidemic the greatest number of cases occurred in the Seventy-first and Fifty-ninth and but few cases occurred in the Ninety-third Company, although it was camped immediately alongside the others. During the recurrence few cases occurred in the other two companies. Several instances of second attacks of influenza in the same individuals were noted, but not in severe or serious form.

With regard to a recurrent outbreak of influenza which occurred at the United States Naval Training Station, Great Lakes, Ill., the following interesting observations were made:

Following the receipt of men from Camp Logan and from the receiving ship at Philadelphia, Pa., after the primary epidemic had passed, both of these stations also having passed through epidemics, there was no noticeable increase in the incidence of influenza at the Great Lakes Station and it was assumed that the new arrivals, who were presumably immune in both instances, either did not bring infection with them or that the station force was also immune by reason of the recent epidemic. On October 27 and October 30 recruits were received from the cities of Atlanta, Meridian, Richmond, Baltimore, Pittsburgh, Nashville, Louisville, and New Orleans. Following their arrival a second outbreak of influenza occurred at the station on November 2, lasting until November 9. During this period 200 cases of influenza occurred, but the disease was

--2480--

confined entirely to recruits from the above-mentioned cities, none of whom had been in camp over five days when attacked, and many were taken ill on the train before arrival. The fact that men who had been on the station for a longer period did not take the disease would indicate immunity.

In the receiving ship at Norfolk, Va., it was noted that only two cases of influenza occurred among the many negro mess attendants quartered on the station during the epidemic.

On the whole it may be concluded that immunity to some degree is conferred by an attack in most instances, but statistics so far have failed to furnish definite knowledge as to the duration of such immunity. It is noteworthy that influenza in the past has recurred in a community year after year for several years in epidemic form following a pandemic, in spite of the fact that from 20 to 30 per cent of the population was attacked during the primary epidemic. It is difficult to believe that some at least of the young adults who developed influenzal pneumonia and quickly succumbed to this complication had not had influenza in a previous year.

Epidemiological studies in civil life indicate that the highest incidence during the fall epidemics was among children and adolescents who, presumably, represented the age groups least likely to have been exposed in previous years. The incidence curve declined steadily through age groups beyond 35, yet no age group proved immune. The children frequently had very mild attacks and epidemic death rates among adolescents and children of school age seem to have been remarkably low. The general death rate among very young children and infants under one year was high during the epidemic, but how many of the deaths were actually due to influenza infection is not yet clear.

The medical world should appreciate the spirit and bravery of the men of the Navy who eagerly subjected themselves to experimentation for the welfare of humanity, for they were warned specifically and they had every reason to believe, as did those who conducted the research work, that they were risking their lives. These volunteers have indeed rendered service to their country and to the world, and the fortunate circumstance that none was seriously harmed does not detract from the significance of this exhibition of high personal courage and of the willingness displayed by all of them to sacrifice themselves for others.

Following is the list of men who volunteered during the Boston experiments:

Abney, Dewey Lavern.
Allan, Robert Andrew.
Anderson, Arthur Raymond.
Bolduc, Joseph Real.
Bullock, Muro Chester.
Calabrese, James Joseph.
Center, Edward Thomas.
Colton, Charles.
Conroy, H.A.
Crist, Bertram.
Crowley, Henry Edward.
Denaard, Arthur Frederick.
Edman, Charles Frederick.
Englert, Henry Joseph.
Felton, James Elwyn.
Fleming, George William.
  Foster, John.
Fournier, Ernest Joseph.
Garriott, Simon George.
Gerow, Percy Hector.
Gibson, Edward Molten.
Goodwin, R.E.
Healy, Thomas B.
Hedges, Daniel Judd.
Kearney, Eugene Aloysius.
Klient, Thomas.
Malone, Walter James.
Marcum, Charles.
Maas, Paul Alfred.
Morrell, William Francis.
Murphy, Leonard Richard.
Murphy, William Joseph.

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McAnneny, John Henry.
McKenna, Joseph Edward.
Nerling, Gustave.
Ortiz, Julius.
O'Toole, Frank Codman.
Peak, George Francis.
Pruett, George.
Reid, Robert Lincoln.
Scott, Robert James.
Slipp, Clarence.
Stanton, Judson Horatio.
Vandermeer, John William.
Vanelli, Arthur Nicholas.
Veteto, Gus Robert.
Vieira, Leopold Joseph.
Wanless, Frank B.
Heine, John Joseph.
Hill, Warren Arthur.
  Holmes, Harrison Stephen.
Aimar, Bertram Hillard.
Crews, Millard.
Dawson, Harvey Allen.
Fink, Herbert Jacob.
O'Neill, Nick Persian.
Evans, Hugh John.
Holziner, Carl Peter.
Warren, Robert Flagg.
Whipp, Raymond Calvin.
Walker, E.F.
Hickey, Edward John.
Jones, Orlando Lloyd.
Lang, William Norman.
Myers, Fred.
Balbian, Frederick.
Campbell, Verlin Everett.
Micks, Albert.

The following men volunteered for the experiments at San Francisco:

Leggett, James Verna.
Oldham, George W.
Eagan, Estis Theodore.
Harrell, Lewis Roy Kendall.
Toombs, Herbert Edgar Lawrence.
Workman, Lester.
Thomas, Franklyn Forrest.
Bennett, J.C., jr.
Combs, Lester Robert.
Swan, George.
Mulcahey, Daniel Vincent.
Taylor, Christopher Anthony Lester, Roy.
Le Duc, Antonio Oliver.
Wages, Vern.
Wall, Lewis Edward.
Lind, Clifford Charles.
Crane, Ellis Madison.
Thompson, Arthur Eugene.
Alsott, Charles Benson.
Lipinski, William.
Tomlins, Roy Lee.
Tegerson, William.
Nardoni, A.M.
Miller, Frank A.
  Burton, Clyde.
Dulaney, Floyd Marcue.
Eskew, Herman Virgil.
Hammer, Adolph.
Shankle, John Swanson.
Tharp, Robert Herman.
Autry, Chalie Lester.
Breco, Davis.
Casson, Jesse Meredity.
Fisher, Earl.
McLaughlin, Joseph Francis.
Lorenz, Joshua H.
Hickson, Samuel Dewey.
Morrow, Ernest James.
Stephenson, Neato Augusta.
Hearing, Elvin.
Bertelsen, Hans.
Dickenson, Lester William.
Bennett, Ray Ernest.
Howard, Fred Elmer.
Christian, Lester O.
McGaughy, Oscar A.
Morrison, M.C.
Callison, George A.
Hohsey, R.L.

Preventive Measures.

First and last, all preventive measures which seemed logical, either from a priori reasoning or because of seemingly good effects claimed for them elsewhere during the year or in previous epidemics, were tried in the Navy.

These included quarantine, daily inspection of personnel and the taking of temperatures, early isolation of the sick, the wearing of face masks and gowns and rigid aseptic technic by attendants upon the sick; the early transfer of patients to a base hospital; the retention and isolation of patients in dispensaries where they could be segregated in small groups instead of being brought into immediate or indirect contact with large numbers of other patients; strict attention to ventilation, relief of overcrowding, use of muslin screens between bunks or hammocks in barracks; prevention of gatherings indoors as much as possible; restrictions on travel, particularly by common carrier;

--2482--

the application of nose and throat sprays to those not yet attacked; the use of prophylactic vaccines, the very general and intensive use of educational measures, and the rigid enforcement of sanitary rules and regulations with particular regard to personal hygiene, cleanliness, care of floors and decks, windows, and other ventilating inlets and outlets, mess gear, drinking utensils, drinking fountains and other articles liable to contamination with mouth and nose discharges of patients or carriers. The protection of influenza patients during convalescence, even those having mild attacks, was generally regarded as an important preventive measure. The therapeutic use of serum donated by patients convalescing from influenzal pneumonia was given a somewhat extensive trial in attempts to reduce influenzal pneumonia case-fatality rates.

Speaking in general terms, the history of influenza in the autumn of 1918 shows that the disease spread rapidly and progressively, attacking communities of all sizes regardless of preventive measures put into effect, and regardless of geographical location, climate, weather, nature of the industries, race, density of population, habits of the people, character of housing, habits of diet, social and economic conditions, sanitation, soil conditions, flora and fauna, or routes and modes of travel.

Naval stations varied greatly in size and density of population as well as with regard to geographical location, environment, and the nature of activities carried on. Strong efforts were made at all stations and on board all vessels to prevent the introduction of the disease and to limit its spread by the enforcement of all preventive measures which were practicable under war conditions. Attention was paid universally to sanitation, education of the naval personnel, ventilation, proper care of mess gear, and early treatment of the sick. Relief of overcrowding was possible in some places; in others, not. Under the necessity of fighting the war it was usually deemed impracticable to establish quarantine of any degree or to prevent intercommunication with civil communities and other naval stations. At different stations various special preventive measures were tried, such as vaccines, use of face masks, daily or twice daily use of prophylactic nose and throat sprays, and putting the men into tents.

Epidemic incidence rates, epidemic death rates, and case-fatality rates varied considerably at different shore stations and among different forces afloat, as the statistical data show. Not infrequently certain specific measures which were credited at one station with having prevented the spread of influenza or with having reduced the complications or with having kept case-fatality rates low failed to prove of any value at another station. So many epidemiological factors were or might have been involved in every instance that it is quite impossible to judge what factors were operative at a given station or to what preventive measures low rates could be definitely attributed when they occurred. It may be said, however, that each of the preventive measures enumerated was thoroughly tried, in conjunction with other measures of course, at some one or more stations where the incidence of influenza was high and the epidemic severe. In other words, each particular preventive measure failed in some instances to accomplish recognizable results.

It should be remarked that influenza was regarded as a disease of the respiratory type disseminated by moist discharges from the

--2483--

mouth and nose, and the preventive measures applied were those which have come to be looked upon as valuable in preventing the spread of any acute communicable disease of the respiratory type. With the exception of absolute quarantine at the United States Naval Training Station, San Francisco, these measures proved of little or no appreciable value in the presence of epidemic influenza.

The experience of 1918 would indicate that a very important preventive measure when confronted with an outbreak of influenza consists in rapidly enlarging existing medical and nursing facilities for the proper care and treatment of the large numbers of persons who will inevitably be attacked regardless of measures planned to prevent the occurrence or spread of the disease.

Quarantine.--Absolute quarantine was imposed at the United States Naval Training Station, San Francisco, on September 23, before the introduction of influenza. All officers, enlisted men, and civilian were recalled and required to remain on the island. All communication with San Francisco and Oakland was discontinued, except to receive supplies and recruits or other men who reported and necessarily had to be received. Precautions were taken to prevent the crews of tugs from approaching persons on the dock closer than 20 feet. All recruits and others who had to be received from the mainland had the pharynx and nasal passages thoroughly sprayed with a 10 per cent solution of silvol and were required to put on gauze face masks before they were allowed to board the tug bound for the island. Upon arrival they were placed in a quarantine camp for several days, during which they wore masks, were sprayed three times a day with silvol, and were required to keep at a distance of 20 feet from each other.

The entire personnel of the station--officers, enlisted men, and civilians were required to have the pharynx and nasal passages sprayed once daily with a 10 per cent solution of silvol. All drinking fountains were flamed with a gasoline torch, and all telephone transmitters were disinfected twice daily. In barracks each cot was provided with a muslin screen extending around the head and along one side, 30 inches above the level of the cot. A part of the personnel was quartered in tents. Outdoor recreation was provided.

This was not a pure quarantine experiment. The entire personnel was inoculated with three successive doses of a mixed bacterial vaccine administered October 12, 15, and 18, respectively. This vaccine contained per c.c.:

Pfeiffer bacillus, Rockefeller strain 5,000,000,000
Pneumococcus type I, various strains 3,000,000,000
Pneumococcus type II, various strains 3,000,000,000
Pneumococcus type III, one strain 1,000,000,000
Streptococcus hemolyticus, two strains 100,000,000

The three doses were 0.5 c.c., 0.8 c.c., and 1 c.c. respectively.

While quarantine was in effect no case of influenza occurred on the station, although all other naval stations on the Pacific coast, as well as civilian communities, experienced epidemics during this period. The disease made its first appearance at the station on December 6, 16 days after quarantine was raised.

In the city of San Francisco the primary epidemic began during the week ending September 21, reached its height during the week ending October 5, and subsided rapidly. The epidemic, as indicated

--2484--

by epidemic death rates, was of about the same duration and severity as those which occurred in Boston, Mass., and Washington, D.C., in spite of the fact that somewhat drastic ordinances and regulations, which included the compulsory wearing of face masks on the street, were adopted; measures which the cities in the East did not see fit to undertake. A rather sharp recurrent epidemic began in the city during the week ending December 14, and the weekly death rate did not reach an approximately normal level until after the week ending March 8, 1919.

At the United States Navy Yard, Mare Island, Cal., very practical precautions were taken as early as September 23, against the introduction and spread of the disease. Absolute quarantine was not feasible but a modified quarantine was ordered. The epidemic in the Mare Island navy yard began October 4, and reached its height in the latter part of the month. The incidence diminished one half in November, but the epidemic period lasted until November 30.

To the absolute quarantine efficiently maintained on Goat Island must be attributed the entire absence of influenza from this training station while all communities in the vicinity were suffering. After free communication was resumed with San Francisco and Oakland on November 21 the disease was introduced, and during the month of December 148 cases of acute bronchitis, 13 of broncho-pneumonia, 4 of lobar pneumonia, and 25 cases of influenza were reported. Doubtless some at least of the cases reported as broncho-pneumonia were true cases of influenza, and judging from the incidence of pneumonic complications at other stations it is altogether probable that at least 100 cases of influenza occurred. The experience at this station seems to show that under exceptional conditions quarantine can be made effective against the introduction of influenza, but that after quarantine is raised the disease will make its appearance with an incidence proportionate to that obtaining at the time in the surrounding territory. Beyond question, life was saved there by the absolute quarantine.

Deaths from influenza and all forms of pneumonia, during the year 1918, occurred at the United States Naval Training Station, San Francisco, as follows:

Week ending-- Influenza
(influenzal
pneumonia.
Pneumonia.   Week ending-- Influenza
(influenzal
pneumonia.
Pneumonia.
Apr. 4 ------ 1   Oct. 15 ------ ------
July 7 ------ 1   Dec. 4 ------ 1
Aug. 21 ------ 1   Dec. 22 2 1
Aug. 28 ------ 1   Dec. 28 1 ------

Unfortunately for epidemiological purposes, the issue was clouded by the fact that the entire personnel received three doses of mixed bacterial vaccine. It is possible, even probable, that such a vaccine would reduce the percentage of pneumonic complications and case-fatality rates in so far as due to secondary invasion by the microörganisms represented, but the evidence adduced elsewhere indicates that the vaccine would not protect against influenza. This was the experience at the marine barracks, Parris Island, S.C.; at Quantico,

--2485--

Va.; at the United States Naval Training Camp, Pelham Bay Park, N.Y., and at the United States Naval Training Station, Great Lakes, Ill. Moreover, among 200 men received at the United States Navy Yard, Mare Island, in a draft from the United States Naval Training Station, San Francisco, at 9 p.m., December 5, three of them were found ill with influenza at 8 a.m., December 6, and during the evening of the same day three additional cases were discovered. On the following day 16 cases developed, making a total of 22, or 11 per cent of the draft, attacked in about 48 hours. This is of interest in connection with the San Francisco experiments discussed on page 422.

It was the opinion of medical officers at the station that spraying of the nose and throat could be eliminated as preventing the disease, because it was used before, during, and after the appearance of influenza cases.

A modified quarantine was imposed at many naval stations. Invariably this measure failed to prevent the introduction of influenza. Influenza proved to be so highly communicable that nothing short of absolute quarantine appeared to have any effect whatever upon the incidence of the disease. At some stations where liberty was restricted and communication with outside sources was reduced to a minimum the epidemic was severe and the attack rate high, while other stations where similar measures were adopted escaped lightly.

The United States Naval Training Camp at Pelham Bay Park furnished an example of the apparent futility of preventive measures in influenza. This station was planned and built in accordance with modern ideas along the lines of preventive medicine. The barracks were comfortable and well ventilated and the men were quartered in comparatively small units. There was a well appointed and well administered detention camp, with separate dispensaries and mess halls. A modified quarantine was in effect at the station. In spite of this the attack rate, the epidemic death rate, and the case-fatality rate were all considerably higher than at the Federal rendezvous, a large armory in a thickly settled section of Brooklyn, N.Y., where the complement was constantly shifting, and where the crew of 1,700 men was berthed in a single large room. No restrictions whatever were imposed on visiting and liberty, because it was not practically to do so. According to all the tenets of epidemiology this station should have suffered worse than the training camp at Pelham Bay Park, situated at the extreme edge of the city limits in a more or less isolated position.

Vaccines.--Experiments in prophylaxis were conducted at various naval stations almost from the beginning of the severe epidemics in the fall of 1918, with vaccines made from pure cultures of the Pfeiffer bacillus; with hemolytic streptococcus and with mixed vaccines containing the three fixed types of pneumococci and several strains of Type IV pneumococci with or without streptococci or Pfeiffer bacilli. Experiments with the Pfeiffer bacillus lead to the conclusion that no protection against influenza was afforded by bacterins prepared from strains of this mircoörganism recovered from the lungs in cases in influenzal pneumonia. Altogether, many thousands of men were vaccinated, with the inevitable result that much conflict of opinion arose from the fact that many individual vaccinated were not subsequently attacked by influenza. Unless properly

--2486--

controlled, vaccination experiments were without value. In the following instances controls were used: Five hundred and fifty-four men in the "incoming detention camp: at the training camp, Pelham Bay Park, N.Y., were given three inoculations of a Pfeiffer bacillus vaccine prepared at the United States Naval Hospital, Chelsea, Mass., and administered in three successive doses, 0.5 c.c., 1 c.c., and 1 c.c. of a well clouded but not counted bacterin. The third inoculations were completed October 5, 1918. On October 10, the 554 inoculated men, together with 800 controls, who had also been held in the incoming detention camp, were released into the main camp. At the time of their release the incidence of influenza in the main camp was decidedly on the decrease and opportunity to contract infection was less than at the height of the epidemic. Nevertheless, 50, or 9 per cent, of the vaccinated men contracted the disease, while only 40, or 5 per cent, of the controls became infected.

Several thousand men were vaccinated at the marine barracks, Parris Island, S.C., in the latter part of October; some with a Pfeiffer bacillus vaccine prepared at the United States Naval Laboratory, Philadelphia, Pa., and some with a similar bacterin which included strains of the Pfeiffer bacillus recovered from patients in the United States Naval Hospital, Chelsea, Mass., prepared at the Hygienic Laboratory, Washington, D.C. Many of the men inoculated were transferred overseas shortly afterwards, and their subsequent histories could not be ascertained. However, a draft of 756 men transferred from Parris Island, S.C., in the early part of November came under observation at the marine barracks, Quantico, Va. Of these, 304 had not been vaccinated, and 39, or 12.8 per cent, contracted influenza within a week after arriving at Quantico. Four hundred and fifty-two men of this draft had received from one to four inoculations of Pfeiffer bacillus vaccine while at Parris island, and 72, or 15.9 per cent, contracted influenza as follows:

A study of the severity of the disease in those not vaccinated, in comparison with those who had received vaccine, indicated that vaccination had no marked influence upon the course and severity of the attack. This conclusion was based on observation of 200 cases of influenza in men who had recently arrived from Parris Island, S.C. The findings were as follows:

Number of cases with no prophylactic inoculation 92
Number of cases with one inoculation 29
Number of cases with two inoculations 40
Number of cases with three inoculations 9
Number of cases with four inoculations    30
  Total number of cases   200
Mild cases:  
  No vaccine 47
  With vaccine prophylaxis    57
     Total cases      104

--2487--

Moderate cases:  
  No vaccine 34
  With vaccine prophylaxis    44
     Total cases      78
Severe cases:  
  No vaccine 7
  With vaccine prophylaxis    11
     Total cases      18

Observation of 281 influenza patients treated in the United States Naval Hospital, Philadelphia, Pa., between October 6 and October 29, 1918, 60 of whom had previously been vaccinated with Pfeiffer bacillus bacterin and 221 not, seemed to show that the incidence of pneumonic complications was decidedly lower in the vaccinated cases. No trustworthy evidence was presented that Pfeiffer bacillus vaccine had any value as a therapeutic agent.

A streptococcus vaccine was used extensively in the thirteenth naval district where responsibility for pulmonary complications and deaths was attributed principally to the microörganism from which the bacterin was prepared. At first regarded as an ordinary hemolytic streptococcus this microörganism was later found to have characteristics similar to those of the Mathers coccus as mentioned above in reference to microörganisms associated with influenzal pneumonia.

The following table indicates the results obtained by the use of this vaccine which was prepared from microörganisms isolated from the blood of living patients and from the tissues in fatal cases. Cultures were nearly always pure. The microörganism could be obtained from the sputum of almost any case and was practically always found in the lung tissues at post-mortem examination. The microörganism easily lost its virulence and hemolytic properties in subculture at 37 C.. and was sometimes indistinguishable from the diplococcus. Proof that there was but a single strain was not furnished and it is not unlikely that the vaccine contained more than one strain. Three doses were administered 48 hours apart, 0.5 c.c., (250,000,000), 1 c.c. (500,000,000, and 1 c.c. (500,000,000).

  Complement. Cases. Per cent
attacked.
Deaths. Case-fatality
percentage.
Vacci-
nated.
Unvac-
cinated.
Vacci-
nated.
Unvac-
cinated.
Vacci-
nated.
Unvac-
cinated.
Vacci-
nated.
Unvac-
cinated.
Vacci-
nated.
Unvac-
cinated.
Philadelphia unit 131 855 37 168 28.2   19.6 0 21 0 12.5
Seattle Training Camp No. 1 ------ 4,159 ------ 813 ------ 19.5 ------ 33 ------ 4.0
Seattle Training Camp No. 2 662 ------ 11 ------ 1.60 ------ 0 ------ 0 ------
Seamen's barracks, Puget Sound 2,800 3,472 57 428 2.03 12.3 0 42 0 9.8
Marines, Puget Sound Navy Yard and ammunition depot 425 ------ 5 ------ 1.2   ------ 0 ------ 0 ------
Filipino unit 111 ------ 2 ------ 1.8   ------ 0 ------ 0 ------
Aviation unit 83 ------ 32 ------ 38.5   ------ 0 ------ 0 ------

It should be said that no unit was divided into two parts for the purpose of running experimental subjects and controls side by side. Circumstances did not permit. In the largest unit (seamen's barracks)

--2488--

many cases of influenza had already occurred before vaccination could be performed; how many is unknown. The same is true of the draft from Philadelphia, but not of the rest of the command.

Conditions of exposure were not materially different in the different units. Housing conditions differed in that some men were in barracks and some in tents, but this seemed to have no effect upon the incidence of the disease. All of the marines were in barracks, rather closely quartered. All of the Seattle Training Camp men were quartered in tents, two men to a tent (8 by 10).

Of 4,212 men who were vaccinated not one man died. Among 111 Filipinos isolated and vaccinated early, and later exposed, there occurred only 2 cases. Among 361 marines vaccinated early, with no attempt to control exposure, there occurred 2 cases, both patients coming down after the first injection. Among 62 marines at the ammunition depot who were vaccinated early there occurred 3 cases--2 after the first injection and 1 after the third. Among 662 sailors at the Seattle training camp, 3 men developed the disease after the first injection, 1 after the second injection, and 7 after the third. Among 83 of the aviation corps there occurred 32 cases, 31 of the patients coming down within a few hours after the first injection and 1 after the third injection. Thus, altogether there were 1,279 men who were vaccinated either before exposure or about the time they were exposed, and of these, 94 developed the disease before vaccination was completed, and 11 afterwards. All recovered. Some of the cases in vaccinated men were fairly severe, and from the blood of one of these patients the diplo-streptococcus mentioned was recovered.

The period of observation was from September 17 to October 21, 1918. Up to November 3, there had occurred but 40 additional cases at the Seattle training camp and 16 at the Puget Sound navy yard, facts which seem to indicate that the epidemic was practically over at the time these data were obtained.

Mixed vaccines were tried at several different stations, but satisfactory controls were not used and war conditions made it impossible to keep track of many of the men vaccinated. The same is true of men inoculated with vaccine composed of the three fixed types of pneumococci. The use of a mixed vaccine at the United States Naval Training Station, San Francisco, Cal., while the station was under absolute quarantine has already been mentioned.

Face masks.--The wearing of face masks by healthy persons was made compulsory at several stations and on board a few vessels. On the whole this was not a practicable measure and little or no good was accomplished by the use of masks. The eyes were not protected. The masks quickly became soiled and required frequent adjustment by the fingers.

Reference has already been made to the three naval air stations in the third naval district, where masks were worn. The attack rates and epidemic death rates were comparatively high at two of them and at the third an epidemic had occurred in the spring.

On board one of the transports all troops and the entire crew were required to wear masks throughout the trip to Europe. The incidence of influenza was very low during the trip and this was attributed by the medical officer very largely to the wearing of masks.

--2489--

However, other transports in the convoy, sailing from the same port at the same time also had very little influenza on that trip without resorting to masks, although the incidence had been high during the previous trip.

No evidence was presented which would justify compelling persons at large to wear masks during an epidemic. The mask is designed only to afford protection against a direct spray from the mouth of a carrier of pathogenic microörganisms; and assuming that it affords such protection, the probability that the microörganisms will eventually be carried into the mouth or nose by the fingers is very great if the mask is worn for more than a brief period of time. Masks of improper design, made of wide-mesh gauze, which rest against the mouth and nose, become wet with saliva, soiled with the fingers, and are changed infrequently, may lead to infection rather than prevent it, especially when worn by persons who have not even a rudimentary knowledge of the modes of transmission of the causative agents of communicable diseases.

On theoretical grounds it is good practice to require those who visit, examine, or wait upon the sick to wear masks. The experience at the United States Naval Hospital, New London, Conn., was typical of that encountered at several other hospitals. "Face masks were worn constantly by medical officers, nurses, and hospital corpsmen while they were in the wards." "The morbidity rate, nevertheless, was very high among those attending the sick, and our experience indicates that if the mask has any value it is simply in preventing an overwhelming dose of infection from direct coughing or other acts accompanied by forcible expulsion of nose and throat secretions." :While it may be taken for granted that masks should be worn by medical officers, nurses, and hospital corpsmen in handling the sick, our observations lead to the opinion that the use of masks in barracks is not a practicable measure of value under ordinary routine conditions." "The very high infectivity of this disease was demonstrated by results in our contagious annex, which is a building especially constructed for the care of communicable disease." "During the past four months patients ill with such diseases as cerebro-spinal fever, diphtheria, measles, mumps, scarlet fever, and German measles have been treated in this building." "Upon occasion, all of these different diseases have been handled at the same time, and the patients have been subsisted from the same diet kitchen, and yet there has been no instance of cross infection." "It may therefore be concluded that the technique was satisfactory; nevertheless, it failed to prevent cross infection in the case of influenza." "A number of medical officers and nurses were infected in that building, and the incidence of the disease was just as high there as in the improvised wards."

At the United States Naval Training Station, Great Lakes, Ill., of 674 hospital corpsmen and volunteers of other ratings who were on duty caring for the sick during the epidemic, 96 wore gauze masks. The others did not. Of the latter, 7.9 per cent developed influenza, while 8.3 per cent of those who wore masks contracted the disease. It will be noted that the attack rate in both groups was much lower than for the personnel in general at the station.

Prophylactic nose and throat sprays.--Nose and throat sprays of various kinds were used at several stations and on board many

--2490--

vessels, not only as a measure applied to the entire personnel in an attempt to prevent the introduction of influenza, but also to check its spread. Those who made use of sprays in a comprehensive way usually felt that good results were accomplished, but comparative statistics do not show this. So many epidemiological factors were operative in all cases and so many preventive measures were tried in addition to spraying that no definite conclusion can be reached from a review of the evidence as to whether or not any great value can be attached to the use of sprays.

At the navy yard, Philadelphia, Pa., an oil-camphor-menthol spray apparatus was installed in the machinery division and a man was kept on duty constantly to spray the nose and mouth of each employee every two hours. The results were reported as satisfactory beyond expectation. "Only two out of a thousand men contracted the disease." Two grains each of camphor and menthol to 1 ounce of liquid petrolatum was used. The liquid petrolatum was regarded as poor culture material, and furthermore it did not wash out the natural protective secretions.

Dobell's solution or alkaline antiseptic solutions were commonly used. Silvol and argyrol solutions were favorites, and chlorinated sprays were used in many places. Solutions of quinine and of zinc sulphate are also mentioned in reports.

Sprays of various kinds were used in the ninth, tenth, and eleventh naval districts and the medical aid to the commandant was of opinion that the procedure distinctly limited the number of cases. The medicament used seemed to be of less importance than the care with which the spraying was done. Reports from numerous stations indicate that cases began to decline in number and severity after spraying was resorted to. Of course, cases usually declined rapidly in numbers and severity as soon as the peak of the epidemic was reached, even though no special preventive measures were undertaken.

If sprays are used it would seem that they should be mildly stimulating but incapable of inflaming the mucous membranes. A spray which causes the mucous membranes to secrete freely may be useful in aiding mechanical elimination of microörganisms which have gained access to the nose or pharynx, but it should be borne in mind that the use of spray apparatus on a number of men in turn is not without danger of becoming a means of disseminating infection.

Another method of applying a medicament to the mucous membranes for prophylactic purposes, and one quite generally overlooked, apparently, was the administration of urotropin to healthy persons during the epidemic. It was observed by a medical officer of the Navy stationed at Los Angeles, Cal., that among 611 persons living in the city, varying in age from 15 to 60 years, who took 6 grains of urotropin three times a day, influenza was contracted in only one instance, the exception being a man of 50 who was irregular in taking his prophylactic doses. The other 610 persons were said to have been exposed to influenza fully as much as their neighbors, many of whom contracted the disease.

Relief of overcrowding.--Overcrowding was undoubtedly an important factor in contributing to the spread of influenza and particularly to the development of complications. However, epidemic

--2491--

influenza was so highly communicable and so many factors besides overcrowding, per se, entered into the causation and propagation of every outbreak that it was impossible in many instances to determine just what the effect was upon incidence rates or upon case-fatality and epidemic death rates.

The Navy was at its greatest numerical strength during the epidemic period and overcrowding at shore stations was very general. The dangers of overcrowding were recognized everywhere but at many stations gross overcrowding could only be relieved by granting liberty freely and allowing men to sleep outside the station. The size of barracks and the number of men occupying one compartment; ventilation; the size of the station (density of population); nature of activities carried on; the arrival of men from other stations bringing new foci of infection or fresh susceptible material; and the character of the epidemic in the environment all had a bearing on epidemic conditions in the station. For these reasons the rates for the principal naval stations in the United States do not reveal clearly the effects of overcrowding although some were more overcrowded than others. The tendency was for large stations to suffer more than small ones. In some instances where there was great overcrowding the rates were not particularly high and in other instances where it could not be said that an unusual degree of overcrowding existed the incidence of the disease was high. Attack rates among the forces afloat were comparatively low although practically all ships were overcrowded.

Taking everything into consideration, careful study of the conditions existing in the Navy during the epidemics leads to the conviction that overcrowding was one of the most serious conditions with which medical officers had to contend in combating influenza and a most important factor in leading to the development and spread of influenzal pneumonia.

In the fourth naval district it was noted that influenza spread more rapidly in barracks than in tent camps. At Cape May, N.J., 150 cases of influenza occurred and while the attack rate was only 8.7 per cent the case-fatality and epidemic death rates were high, 9.3 and 8.1 per thousand respectively. During this epidemic period (September, 1918) no case occurred at the section base, Cape May, where all men lived in tents. Very few cases occurred at the coastal air stations where about half of the complement was quartered in tents. The more or less isolated positions of these stations and the absence of congestion of population in the environment are to be considered.

At Newport, R.I., in order to make room for the care of the sick, 1,000 men were transferred from the receiving barracks at Cloyne Field and quartered in large pyramidal tents on the Vanderbilt farm, September 15. "Cases of influenza continued to develop in large numbers for three days only, the epidemic among this personnel practically terminating on September 19, despite cold, rainy weather." "Removal to the tent camp in the country appeared to check the epidemic." However, the epidemic at the training station, near Cloyne Field, where many of the men were quartered in barracks similar in type to the receiving barracks, was also practically over on September 19. At the training station a portion of the complement

--2492--

was quartered in small tents and the men in these suffered equally with those in barracks.

At Block Island, R.I., the personnel at the section base was moved into tents because it was noted that cases of influenza developed only in men subsisted in the civilian community. No case occurred subsequently. At the section base, Woods Hole, Mass., also located in an isolated position, only a few cases of influenza developed among the complement of 188 officers and men during the period of severe epidemics in September and October, but a local outbreak occurred during the week ending November 30, resulting in 22 cases of influenza and 1 death from pneumonia.

In the receiving ship at Boston (Commonwealth Pier), which was grossly overcrowded when the epidemic began, arrangements were made at once to establish a tent camp. From September 20 to November 1, the average complement of the receiving ship was more than 4,000. Of that number, approximately three-fifths were under canvas at Framingham, Mass. During this period, although the primary epidemic had passed, there were 157 cases of influenza, of which 140 occurred in Commonwealth Pier and only 17 in the tent camp at Framingham, in spite of the fact that more men were quartered in the camp.

Ventilation.--The mass of data covering influenza in the Navy during 1918 contains much evidence that the degree of ventilation had an important bearing on the spread of the primary disease as well as on the dissemination of the microörganisms which as secondary invaders appeared to be largely responsible for fatalities. In fact, the enforcement of good ventilation stands out as one of the few preventive measures among those generally applicable which may be expected to have a definite influence in checking the spread of influenza and to make for a low epidemic death rate.

On board ship and at naval stations the operation of many other factors made it quite impossible to study the effect of ventilation by itself and the conclusion reached is rather a conviction formed by reading detailed reports of many epidemics, taking into account all attending circumstances, than one based on incidence and mortality figures. The statistics for an entire station are unsatisfactory in practically all instances for a study of the effect of good or bad ventilation.

The fact that the air was constantly in motion and rapidly removed from a room or compartment often seemed to bear a direct relation to a lower incidence rate and a lower percentage of fatal or complicated cases than in barracks or ships where ventilation was less adequate. Without minimizing the importance of the "droplet spray" as a means of transmission it is reasonable to assume that for a short time nose and throat discharges in finely divided particles may float in the air where they may convey microörganisms to other persons not necessarily in close contact. With good ventilation such material is constantly being removed.

Reports from ships indicated in several instances that the incidence of influenza was lower in well-ventilated compartments than in other compartments. It was noted during an epidemic on board the U.S.S. Orizaba, en route to Europe, that many cases occurred among troops who were quartered in a troop compartment on the

--2493--

port side where very weak currents of air were issuing from ventilator outlets while practically no cases occurred on the starboard side where the air supply was abundant.

The United States Naval Aviation Detachment, Bolsena, Italy, was housed in barracks under exceptionally good conditions with regard to ventilation. Each man had 1,080 cubic feet of air space and free ventilation was maintained constantly. At a neighboring Italian station there was considerable overcrowding, each man having approximately 270 cubic feet of air space. It was the custom here to keep the windows closed and it appeared that extra precautions were taken during the influenza epidemic to guard against too much fresh air by the use of canvas curtains around bunks and by caulking all cracks with cloth. In the city of Bolsena the same fear of fresh air was noted. "Frequently 8 to 12 persons were found sleeping in dark, low rooms of perhaps 10 by 18 feet, with the one window closed and padded to secure extra protection against fresh air."

The essential epidemiological data were as follows:

  U.S. Naval
Aviation
Detachment.
Italian
station.
City of
Bolsena.
Length of epidemic 6 days 40 days 57 days
     United States detachment, Oct. 8-13.      
     Italian station, Oct. 1-Nov. 10.      
     City of Bolsena, Sept. 28-Nov. 23.      
Complement 58 579 3,800
Cases of influenza 13 185 700
Percentage of complement attacked 22.41 31.9 18.42
Complications None 32 252
Broncho-pneumonia None 32 180
Deaths None 9 45
Case-fatality rate, per cent   4.86 6.42
Epidemic death rate   1.50 1.18

In Guantanamo City, Cuba, during the epidemic, as observed by medical officers of the Navy, the incidence of influenza was very high and the disease was very fatal, especially in the cases of Haitians and Cubans, among whom sanitary conditions were bad and the practice of tightly closing all doors and windows was followed. In Caimanera and Boqueron, on the other hand, where sanitation was supervised and good ventilation insisted upon the mortality was extremely low.

Influenza was introduced into Guam October 26, 1918, from Manila, P.I., and spread rapidly. Only a few individual escaped attack, so that the case-fatality rate was practically the epidemic death rate. Approximately 4.5 per cent of the native population died.

Case-fatality rates by age groups.
  Per cent
Under 5 years 22.55
5 to 10 years 4.98
10 to 20 years 3.10
20 to 30 years 4.55
30 to 40 years 6.72
40 to 50 years 9.76
50 to 60 years 14.72
60 to 70 years 16.70
Over 70 years 16.92

--2494--

"Apparently the causative agent was spread by the air, which may probably be explained by the high degree of relative humidity prevailing on this climate." "Large numbers of persons were attacked simultaneously by the disease, although so far as known they had not been in close contact with the sick." "Native houses are built entirely too close together, and entirely too many people live in the same house." "The people crowd into these houses and sleep on mats spread on the floor with windows and doors tightly closed." the majority of cases among Americans were very mild and only one resulted fatally, a case of broncho-pneumonia in a carpenter's mate, second class. All medical officers and all but three nurses contracted influenza.

In the Philippines the disease early assumed grave proportions among the native population, spread rapidly, and caused many deaths. It even spread to the leper colony at Culion, where the death rate was very high. The same fulminating types seen in other parts of the world were noted and in the early part of the epidemic the diagnosis of pneumonic plague was seriously considered in one case. Taken altogether the enlisted personnel of the Navy and Marine Corps, including native forces, really suffered from influenza very slightly. The incidence among nurses and hospital corpsmen was low.

Among natives in Olangapo the attack rate was between 30 and 35 per cent; the epidemic death rate, approximately 8 per thousand, and the case-fatality rate, about 2.5 per cent. "The mortality among the very young and the very old and those affected with tuberculosis, of which there were many, was very high." Overcrowding in stuffy shacks is the prevailing custom among the natives. Doors and windows are closed tightly at night, but as a rule there are upward drafts through the bamboo floors. During the greater part of the epidemic period the weather was windy and inclement.

In brief, Navy reports from Guam, the Philippines, China, Japan, Cuba, Haiti, Santo Domingo, and Nicaragua indicate that influenza among Americans and European was a milder disease than among natives, and that relatively fewer were attacked.

While one may readily believe that insistence upon good ventilation with as many changes of air per hour as can be secured without causing real discomfort is an important preventive measure, the instances cited show how unsatisfactory attempts are to prove this directly from data accumulated during the epidemics. In almost every instance, bad ventilation was intimately associated with overcrowding and other insanitary practices. Density of population and individual susceptibility are to be considered also.

Use of screens in barracks between bunks or hammocks.--This measure was very generally adopted. Like other measures based on the assumption that modes of transmission in the case of influenza are those of communicable diseases of the respiratory type the use of screens would appear to be an important preventive measure, especially with a view to limiting the dissemination of pneumococci, streptococci, and other known microÖrganisms. The means of transference other than under sleeping conditions were infinite and epidemic influenza proved to be so highly communicable that it is not to be expected that direct evidence of the efficacy of screens would be forthcoming.

--2495--

Disinfection of articles liable to contamination with nose and throat discharges.--It is the ordinary practice in the Navy to sterilize all mess gear and the dangers of the "common drinking cup" are universally recognized. Extra precautions were taken everywhere throughout the epidemic period to prevent possible infection from such sources. In all probability chances for infection in this way occurred in isolated instances but there is no direct evidence to show that such articles were the means of disseminating influenza in the Navy. It is obviously impossible to judge the part played by towels, handkerchiefs, pipes, Bull Durham bags, and numerous other articles subject to transfer from one person to another.

Restriction of gatherings indoors.--At most stations steps were taken to keep the men out of doors. In many instances, Y.M.C.A. buildings were closed and indoor recreation was suspended. The effect of such measures is still problematical. It is to be borne in mind, however, that by closing centers of entertainment and recreation it is frequently possible to do more harm than good in congested stations. In a large naval station where overcrowding exists, and especially where the environment is a large and congested city, it is perhaps better to keep such centers open, paying due attention to ventilation. At a small station in a more isolated position it may be advisable to prevent gatherings indoors.

Daily inspection of the entire personnel.--This measure is always indicated in the Navy when an outbreak of any communicable disease of the respiratory type threatens. The procedure was not always practicable during epidemics of influenza, particularly at the larger stations. At the United States Naval Training Station, Hampton Roads, Va., "morning temperatures" were taken of as many of the personnel as possible. Those having a rise of temperature, even through they felt perfectly well, were placed on the sick list and isolated, for experience had shown that the majority usually developed symptoms of influenza later in the day.

In the receiving ship at Norfolk (St. Helena Station) a daily morning and afternoon inspection of the entire personnel was instituted. Men showing various degrees of temperature elevation were segregated for observation. About 60 per cent of these developed typical symptoms of influenza, but upon questioning them it was learned that practically all had suffered with "colds" or headache prior to having been picked from ranks, although they had not considered themselves sick enough to go to the sick bay. Among those showing a rise in temperature not followed by the development of influenza the elevation was attributed to various causes: No disease, 14 per cent; acute rhinitis, 11 per cent; autointoxication, 6 per cent; constipation, 5 per cent; acute otitis media, 1 per cent; acute tonsillitis, 1 per cent; acute pulmonary tuberculosis, 1 per cent; diagnosis undetermined, 1 per cent.

Early isolation of the sick.--This was universally recognized as an important preventive measure, as it is in the case of any communicable disease, for the protection of those who might otherwise be exposed. It is particularly important to put the influenza patient to bed as soon as possible for his own welfare.

In some instances the question arose as to whether it was the best policy to isolate patients in dispensaries and barrack buildings set

--2496--

apart for the purpose or to transfer all patients to hospital. In many instances there was no choice in the matter. All accommodations for the care of the sick were required so that the more serious cases were transferred to hospital, those moderately ill were kept in dispensaries, and mild cases were treated in barracks.

No matter what the circumstances under which patients were treated, experience would indicate that the use of screens between beds, with a view to preventing cross infections, was a most important measure. The greater the number of patients the more danger of cross infection. Uncomplicated cases of influenza should not be treated in the same ward with cases of influenzal pneumonia, and the latter should be adequately screened ipso jure with the hope of preventing cross infection among themselves. It was not always possible wholly to separate uncomplicated cases from cases of influenzal pneumonia. It was always possible to institute an aseptic technique and modified cubicle system, improvised by means of screens.

On theoretical grounds it would seem to be the better policy, where reasonably good care can be given, not to send influenza patients to a central hospital during an epidemic if it can be avoided, the risks of complications being less when patients are treated alone or in small separated groups. It would also appear that if patients must be transferred to hospital they should be transferred early in the disease. After pulmonary complications have set in, removal is often hazardous and, as in the case of measles, exposure of the influenzal pneumonia patient to the cold or fatigue incident to a long ambulance ride is liable to be exceedingly dangerous. In civil communities it is very questionable if influenza patients, even those in poor circumstances, should be transferred to hospital if good ventilation can be secured in the home, if proper nourishment can be had, if there is an intelligent person to wait upon the patient, and particularly if the services of a district or visiting nurse are available. Ordinary medical skill often seemed to avail more under such circumstances than the services of highly trained internists under the best hospital conditions obtainable during the epidemic. In the Navy, service conditions sometimes make it expedient to transfer a patient to the base hospital when a case similar in character would not be removed in a civil community.

It was the consensus of opinion among many observers that the patient is fortunate who can go to bed at once and remain there until free of fever and until his strength begins to return.

It was observed in the receiving ship at Norfolk (St. Helena Station) that the period of early convalescence appeared to be a time of great danger to the patient, for he was then extremely susceptible to pneumonia. Feeling more comfortable, though weak, he was apt to become restless and expose himself rashly, possibly getting out of bed and walking to the toilet with bare feet. Under such circumstances definite symptoms of pneumonia not infrequently developed within a few hours. Several patients developed broncho-pneumonia after two days of normal temperature where there had been non exposure and where the nursing was careful and competent. However, it was the conviction of medical officers at this station that "early to bed, avoidance of chilling, and fresh air treatment" will many times prevent complications.

--2497--

At the marine barracks, Quantico, Va., it was the practice to discharge all influenza patients into a convalescent camp, separating patients who were coughing from the others. Approximately 10 per cent of convalescent patients subsequently had fever after four days of normal temperature. In the isolation hospital at that station all influenza patients who developed pneumonia were at once removed to a separate ward.

At the United States Naval Air Station, Pauillac, France, there were few complications during the epidemic, and it was reported that there were fewer deaths than among other organizations on the coast. No special preventive measures could be instituted among the personnel at large because of imperative industrial demands of war. The low mortality was attributed to putting every patient to bed as soon as he complained of feeling badly, thorough spraying, and absolutely no moving or transferring.

Experience at the United States Naval Training Station, Great Lakes, Ill., led medical officers to believe that transfer of patients to hospital tended to increase the number of cases in which pneumonic complications developed. A similar belief was held by the medical officer of the officer material school, Pelham Bay Park, New York, who reported that mild cases of influenza were not transferred to hospital because of a belief that fewer complications would result if not transferred. He remarked that repeated exposure of patients with cough certainly predisposed to the development of pneumonia.

At the United States Naval Hospital, Philadelphia, Pa., Pa., among 362 cases admitted to hospital during the epidemic within 24 hours of the onset of influenza, the case-fatality rate was 2.8 per cent; among 197 admitted within 48 hours, 8.6 per cent; among 116 admitted between 48 and 72 hours after onset, 30.2 per cent, and among 235 cases admitted after 72 hours, 30 per cent.

At the United States Naval Hospital, Great Lakes, Ill., the case-fatality rate among 2,924 cases of influenza transferred to hospital was 30.5 per cent. Of these cases 1,807 had pneumonia, making a case fatality rate of 46.2 per cent for influenzal pneumonia. For the 2,924 cases of influenza the average duration of illness before admission to hospital was 5 days.

At all naval stations confronted with fulminating outbreaks of influenza, the cases which developed complications and those which in the judgment of medical officers promised to be serious from the beginning, were the ones principally transferred to hospital. Such selection of cases was usually necessary for the conservation of both hospital and dispensary beds.

Fatigue.--The determining factor in the development of influenza appears to be lack of specific immunity and certainly a high percentage of all persons seem to be susceptible at one time or another when the disease is prevalent. Nevertheless, the element of fatigue seems in many cases to have played a part in the development of complications.

Experience at the United States Naval Training Station, Newport, R.I., indicated that fatigue was responsible for a certain number of the cases of influenza and the schedule of instruction for incoming recruits was rearranged so as to be less fatiguing than under the former system. This change seemed to be beneficial.

--2498--

Observations made by a medical officer of the Navy at the large post at Gievres, France, which was divided into subposts A, Engineer; B, Medical; C, Ordnance; D. Quartermaster; E, West End; F, Quartermaster, seemed to indicate a close relationship between the incidence of influenza, particularly the severe cases, and physical fatigue, long hours of uninterrupted labor with no relaxation from routine duties, no entertainment or change of scenery, and exposure to cold, inclement weather. The quartermaster and labor organizations suffered much more heavily than other organizations.

That there is evidence to the contrary in respect to fatigue and exposure, as there is in relation to all other epidemiological factors, is shown by experience on board the U.S.S. Lebanon during the epidemic period. It was regarded as remarkable that no case occurred on board, in spite of the fact that no precautions could be taken to prevent the introduction of influenza other than to keep berthing spaces well aired, to sun bedding, and require men to shift into dry clothing after the day's work was done. The crew was exposed to all kinds of weather. Men were frequently wet from the waist down, and they worked long hours both day and night in the preparation of target rafts for gunnery practice.

Travel.--Influenza is spread by travel. Attempts were made in the Navy to reduce travel between stations to a minimum consistent with the requirements of war. The history of the disease in the United States during the autumn of 1918 shows that it was carried speedily to all parts of the country by travel among civilians. In spite of all efforts to limit the transfer of men, influenza was spread by a draft of men from Boston to the navy yard, Philadelphia, Pa., and from there directly to the navy yard, Puget Sound, Wash., by another draft. Unquestionably the disease would have reached these stations in the course of a short time via the civilian communities. Nevertheless, it would seem advisable to stop travel between naval stations and between stations and ships during the course of an influenza epidemic or when an epidemic threatens, in the attempt to prevent by all possible means the introduction and spread of the disease from one ship or station to another on the principle that the longer the development of an epidemic can be delayed the less likely is the epidemic death rate to be high.

The conditions under which drafts are moved by rail, more especially for long distances, almost always involve such predisposing influences as overcrowding, bad ventilation, interrupted sleep, and irregular meals, and frequently poorly-heated cars in cold weather.

Educational measures.--The importance of educational measures was fully appreciated by medical officers who disseminated information on influenza among the personnel generally by means of talks, bulletins, and posters.

The bureau issued a warning in the weekly bulletin, Notes on Preventive Medicine for Medical Officers, United States Navy, of August 9, 1918, that influenza had again assumed pandemic proportions and thereafter sought to inform medical officers promptly of developments and to supply them with information of an educational value week by week, as fast as knowledge was acquired during the course of the epidemics, which proved to be of unprecedented severity.

--2499--

The following are samples of circulars and posters published at various naval stations:

 

MARINE BARRACKS, QUANTICO, VA.

PROTECT YOURSELF FROM SPANISH INFLUENZA, DIPHTHERIA, SCARLET FEVER, SORE THROAT, MUMPS, BAD COLDS, GRIPPE, TONSILLITIS, MENINGITIS, TUBERCULOSIS, MEASLES, WHOOPING COUGH, PNEUMONIA.

The above diseases are transmitted through the secretions of the mouth and nose of sick people or "carriers." "Carriers" are persons who do not show symptoms of the disease, yet harbor the germs.

  1. Measures taken to avoid the germs or "bugs" causing the diseases.

    (a) Avoid

    Overcrowding.
    Common drinking cups.
    Promiscuous spitting.
    Stay away from one who is coughing or sneezing as minute infectious materials are expelled into the air by this process. When you cough or sneeze, do so into a handkerchief, or else bend your head downwards.
    Do not put into your moth, fingers, pencils, or anything else that does not belong there.

    (b) Promote

    Free ventilation; keep windows open as much as consistent with the climate. This causes dilution of the impure air and renders it less infectious.

  2. Measures taken to avoid lowered resistance to disease.

    (a) Avoid

    Constipation.
    Excessive fatigue, worry, or mental exhaustion.
    Unnecessary exposure to cold or wet.
    Change wet clothing whenever necessary, especially shoes and socks.

    (b) Promote health by

    Frequent baths followed by a brisk rub down.
    Mild physical exercises.
    Drink one or two glasses of water on rising.
    Keep well covered with blankets at night.
    Brush teeth regularly.
    Wash your hands before each meal.

W.L. MANN,
Lieutenant-Commander, Medical Corps, U.S.N., Post Surgeon.

Approved:


NOTICE

UNITED STATES NAVY YARD,
Mare Island, Cal., September 25, 1918.

INFLUENZA.

1. Influenza, Spanish influenza, or grippe, has made its appearance in the Eastern and Middle Western States in the form of a rapidly spreading epidemic. Since it will undoubtedly be carried here the following information is given in order that you may be in a better position to prevent its spared, thereby protecting the members of your household and your neighbors.

2. No other communicable disease which assumes epidemic proportions spreads so rapidly or attacks so large a proportion of the population, no age, sex, or class of society being immune.

3. The infectious agent is the influenza germ which is carried by the secretions of the nose and mouth.

4. The modes of infection are (1) directly from the infected individual by coughing, spitting, sneezing, or by in any way coming in contact with the nasal

--2500--

or mouth secretions; (2) by indirect methods through contact with articles soiled by the above-mentioned secretions, such as handkerchiefs, towels, mess-gear, etc. In this connection it must be remembered that the disease germs often persist in the nose and throat for some time after the symptoms of the illness have subsided.

5. The incubation period is very short, one to four days, average two.

6. Methods of control.--(1) Early recognition of the case: In order that cases may be early recognized a brief description of the onset and symptoms is given. Onset usually rapid, with a chill followed by fever from 102° to 104°, great depression, weakness, dizziness, severe headache, backache, pains, and soreness of muscles and joints all over the body. The throat may feel sore, the eyes are congested and do not bear the light well. There are practically always symptoms of a bad cold, with running eyes and nose, soreness and tightness of chest with coughing. Anyone presenting the foregoing symptoms, or any one of them should report at once to a medical officer. (2) When the case has been recognized, rigid isolation must be carried out; only one attendant for each case; attendant must wear gown and gauze face mask.

7. Concurrent disinfection must be practiced to include all articles which have come in contact with the patient such as clothing, bedding, messgear, books, papers, letters and all personal belongings of attendant. Careful nursing in a warm, well ventilated room is an essential part of the treatment. Pneumonia is a common complication.

8. Terminal disinfection, thorough cleansing and airing of the compartment occupied and sterilization of all linen and bedding of patient.

9. Vaccination against influenza is partially successful.

10. General methods to prevent the spread of infection.

  1. Avoid crowded assemblages during the epidemic such as theaters, picture shows, public gatherings of all kinds.

  2. Avoid traveling on congested public conveyances.

  3. Do no cough, spit, or sneeze promiscuously; always use your handkerchief over your mouth when coughing or sneezing.

JOHN L. NIELSON,
Commander, Medical Corps, United States Navy.

Approved:


COMMANDANT'S ORDER
No. 386
UNITED STATES NAVY YARD,
Mare Island, Cal., September 24, 1918.
Subject: Precautions to be observed in anticipation of an epidemic of influenza at Mare Island.

  1. Commanding officers shall comply as far as practicable with the following regulations:

    1. No recruits or drafts to be sent to this station until the probability of an epidemic no longer exists.

    2. Sleeping space per man to be 50 square feet; overflow to be placed in tents.

    3. Cubical isolation to be established by hanging curtains between bunks or cots and between hammocks. Sheets and other available material may be used for this purpose.

    4. A copy of this notice to be conspicuously posted, and all enlisted men and civil employees to be made acquainted with the contents thereof.

  2. It is impossible to establish a strict quarantine at this yard without closing the yard, and no efficient separation between civilians and military personnel can be established. A modified quarantine as follows is hereby directed:

    1. Continue 21-day detention of all arrivals as at present.

    2. When cases develop in adjacent towns stop liberty; stop congested gatherings of personnel, such as theaters, moving pictures, recreation rooms, reading rooms, churches, class rooms, etc. Permit only drills, amusements, and instruction in the open air.

    3. Strict isolation of cases of the disease with concurrent and terminal disinfection. Attendants on cases to wear gowns and face masks, and to observe strictly the disinfection of the hands after handling cases. Cubicle isolation of patients, as above provided, to be complied with.

--2501--

  1. All spoons, knives, forks and cups, and other articles of mess gear to be boiled in dishwashing machines for a period of five minutes. Competent persons are to be detailed to see that this provision is carried out.

  2. Fatigue of personnel to be reduced by limiting drills and other military exercises. Clothing protection to be ample, and latitude to be permitted consistent with the maintenance of discipline. All washable clothing to be steam laundered, especially handkerchiefs and towels.

  3. The swimming pool is to be given a little chlorine in excess of that used at present, and is to be closed entirely if influenza appears on the station.

  4. All sanitary drinking terminals with globe tips to have the porcelain globular portion of the terminal removed.

CARE OF SICK.
  1. Additional personnel to cope with an anticipated epidemic has been requested by the commandant. Provision for temporary hospital facilities for sick, within the limits of the naval training camp and marine barracks, to be accomplished either by hospital tents or the assignment of certain barrack buildings for that purpose. Severe cases, or those developing into pneumonia, to be sent to the naval hospital; mild cases may be cared for in temporary hospitals established in the camps.

  2. Provisions for the care of civilian sick to be established at the island, such civilian cases to be limited to those individuals who have no home where they can be nursed and fed while sick. The naval hospital has arranged to care for severe cases and pneumonia among civil employees, and, if necessary, mild cases may be treated in temporary hospitals at camps or temporary hospital near yard dispensary.

HARRY GEORGE,
Captain, U.S. Navy (Retired), Commandant.


U.S.S. "MISSISSIPPI," September 15, 1918.

Subject: (a)Sanitary Bulletin No. 6.
  (b) Influenza.

1. Influenza or "grippe" is more contagious than measles. Though it is common enough at all times, there have been several epidemics. In 1889-90 there was a world-wide epidemic in which three-fourths of our city populations were affected. It is caused by a germ--the bacillus of influenza. The infection is introduced through the nose and throat. It spreads most rapidly where people are crowded, as on a ship, because the air becomes filled with germs from the coughing and sneezing of those who have the disease. It is like a "common cold," but is of greater severity.

2. Symptoms.--It may begin within a few hours after infection, or may not appear for several days. It begins suddenly with fever, headache, pains in back and shoulders, and feeling of weakness. Coughing and sneezing appear early in the attack. The cough is at first dry and hacking, and may be accompanied by the sensation of suffocation. There are many complications which occur. Pneumonia appears to be common in this epidemic. After recovery a feeling of depression is liable to last a long time.

3. Prevention.--It is a dangerous disease and will, if we should have many cases, make it difficult to "play the game." We have not a single case aboard. Help us to keep clear of it.

If you rate a "48," paste this in your hat:
Avoid the hug,
Avoid the lip,
Escape the bug
That gives the "grippe."

Approved for publication.

(Signed) B.F. HUTCHISON,
Captain, United States Navy, Commanding.

--2502--

U.S.S. "MISSISSIPPI," October 8, 1918.

Subject: (a)Sanitary Bulletin No. 7.
  (b) Present status of influenza.

1. Influenza is with us, but it is mild. We have had very few cases, and the majority of these have not been severe. We have fared better than the other ships in the fleet. A number of deaths have been reported from other ships. We have not had a single death. Only three of our patients have been sick enough to necessitate transferring them to the hospital ship, and these are now on the road to recovery. We now have 15 cases, and 8 have been returned to duty. These fine results are not a matter of luck; they are due to the splendid cooperation of the officers and men of the Mississippi. Keep up the good work.

2. When coughing or sneezing place a handkerchief in front of your face.

3. Swing your hammock head to foot.

4. Keep out of crowds.

5. Don't use anyone else's towel, handkerchief, or cup.

6. Get lots of fresh air.

7. Report at sick call if you have a "cold."

8. A clean ship is a healthy ship. Clean 'em up, Mississippi.

Approved:

(Signed) B.F. HUTCHINSON,
Captain, United States Navy, Commanding.

 

The Bureau of Medicine and Surgery published the following circular for use in the Navy Department during the epidemic in Washington, D.C., and copies were distributed also at various naval stations:

[Circular No. 1.]

DIVISION OF SANITATION,
Washington, D.C., September 26, 1918.

INFLUENZA

Influenza is "grippe." It is now spreading over the country in epidemic form. The last extensive epidemic occurred in 1889-90, and the disease was very prevalent for several years after.

The present epidemic disease is plain influenza. The term "Spanish influenza" has been applied because of its recent prevalence in Spain. Influenza occurs every year in the United States, but it is more contagious during an epidemic, and pneumonia is a more frequent complication.

Influenza is caused by a germ, the influenza bacillus, which lives but a short time outside of the body. Fresh air and sunshine kill the germ in a few minutes.

The disease is spread by the moist secretions from the noses and throats of infected persons.

Protect yourself from infection, keep well, and do not get hysterical over the epidemic.

Avoid being sprayed by the nose and throat secretions of others.

Beware of those who are coughing and sneezing.

Avoid crowded street cars--walk to the office if possible.

Keep out of crowds--avoid theaters, moving-picture shows, and other place of public assembly.

Do not travel by railroad unless absolutely necessary.

Do not drink from glasses or cups which have been used by others unless you are sure they have been thoroughly cleansed.

You can do much to lessen the danger to yourself by keeping in good physical condition.

Avoid close, stuffy, and poorly ventilated rooms--insist upon fresh air, but avoid disagreeable drafts.

Eat simple, nourishing food and drink plenty of water. Avoid constipation.

Secure at least seven hours sleep. Avoid physical fatigue.

Do not sleep or sit around in damp clothing.

Keep the feet dry.

Influenza usually has a sudden onset with chilliness, severe headache, and "aching all over." At times the disease begins with nausea, vomiting, and abdominal pain. Fever begins early. Frequently catarrhal symptoms do not appear until later. When they do they are the symptoms of a bad cold in the

--2503--

head with a raw throat and dry cough. Weakness and prostration out of proportion to the fever are common. Former epidemics have been characterized by marked mental depression. In the present epidemic many of the cases are having a gradual onset--more like a gradually increasing cold in the head.

Practically, the great danger from influenza is pneumonia, which tends to follow in a considerable percentage of the cases.

For the protection of others, if your are really sick stay at home and remain there until the fever is over. A day in bed at the very beginning may also save you from serious consequences later on.

If you are up and about, protect healthy persons from infection--don't spray others with the secretions from your nose and throat in coughing, sneezing, laughing, or talking. Cover the mouth with a handkerchief. Boil your handkerchiefs and other contaminated particles. Wash your hands frequently. Keep away from others as much as possible while you have a cough.

If you become ill don't try to keep up with your work. Fight the disease rationally and do not become unduly alarmed. In the average case recovery from acute symptoms follows in five or six days. To hasten recovery and lessen the danger of complications, go to bed at once and keep the body warm. There should be plenty of fresh air, but chilling is to be avoided. At the beginning of the disease a cathartic, such as 21/2 or 3 grains of calomel, followed by a seidlitz powder or epsom salts, is useful. Aspirin in 5-grain doses is useful for pain, but do not take large doses of aspirin, phenacetin, or other medicines. Send for the doctor.

 

Therapeutic use of the serum of convalescent influenzal-pneumonia patients.--At the United States Naval Hospital, Chelsea, Mass., the treatment of influenzal pneumonia with serum obtained from patients convalescing from influenzal pneumonia was begun early in October. In all, 151 patients were treated, of whom 6 died, making a case-fatality rate of 4 per cent. Most of these cases were treated early in the course of the pneumonic complication. The average dose of serum was 120 cc. Lieutenant Commander L.W. McGuire and Lieutenant W.R. Redden, Medical Corps, United States Navy, who conducted this work concluded that "pooled serum from convalescent influenzal broncho-pneumonia patients at this hospital has greatly reduced mortality, has shortened the course of the disease, and has proved almost a specific, not only during a waning epidemic but also during the more recent severe recrudescence." The recrudescence referred to included cases from the U.S.S. Yacona previously mentioned in connection with experimental attempts at the Boston station to transmit influenza to volunteers. The best results were secured in cases showing leucopenia. The outcome of streptococcus pneumonia cases was not influenced much by the serum treatment and therefore serum was not administered in cases diagnosed as streptococcus pneumonia by lung puncture. Apart from this, the cases treated with serum showed striking and immediate improvement clinically in most instances.

At the United States Naval Hospital, Washington, D.C., Lieutenant F.W. Hartman, Medical Corps, United States Navy, reports that of 567 cases of influenza, 157, or 27 per cent, developed pneumonia. One hundred and eleven were not treated with serum. Of these, 28 died, making a case-fatality rate of 25.2 per cent. Forty-six cases were treated with serum from patients convalescing from influenzal pneumonia, with the result that there were only 3 deaths or a case fatality rate of 6.5 per cent. Pneumococcus empyema was found in two of the fatal cases, and streptococci were recovered by lung puncture in the third.

At the United States Naval Hospital, Parris Island, S.C., 48 cases of influenza pneumonia were treated with serum from patients convalescing

--2504--

from influenzal pneumonia with 35 recoveries and 13 deaths, making a case fatality rate of 27 per cent. During the early part of the epidemic it was impossible to follow the blood counts closely but with two or three exceptions the usual leucopenia was noted. Leucopenia gradually disappeared with improvement in the patient's condition. The serum did not cause a sudden increase in the leucocyte count. Serum from convalescent influenza patients was apparently of little value. There was considerable variation in the potency of serum donated by different patients convalescing from pneumonia. One donor yielded 500 c.c. of serum and invariably the recipients of his serum showed marked improvement even after that from other donors had failed to relieve symptoms. Lieutenant Commander J.A. Bass and Lieutenant C.E. Ervin, Medical Corps, United States Navy, who reported these cases concluded, "In spite of the high mortality rate, as noted above, we are satisfied beyond the shadow of a doubt that the use of serum from convalescent influenzal pneumonia patients is of marked value in the treatment of influenzal pneumonia." "The sooner the treatment is begun the better the prognosis." "Treatment was not withheld in any instance because the patient seemed hopelessly ill when first seen."

At the United States Naval Hospital, Great Lakes, Ill., it was concluded that the use of serum from convalescent patients was of practically no account. During the early part of the epidemic patients received were desperately sick and conclusions were held up with regard to this treatment. Later, when fresher cases were received the good results that others reported were not obtained.

On board the U.S.S. Solace (hospital ship) the supply of human serum was limited and was only administered to those patients who were critically ill. Of nine cases treated, two died. One of these was admitted in a moribund condition. In the other fatal case the findings were double pneumonia, pneumococcus septicemia and pneumococcus (Type III) meningitis. From one to eight doses of serum were administered in the remaining seven cases. In three instances improvement was rapid; in the others more gradual, but the medical officers in charge of the cases had no doubt that the serum produced beneficial results.

Pneumonia.

As a cause of death the pneumonias, both lobar pneumonia and broncho-pneumonia complicating other diseases, are far in the lead of all other causes. Of the 5,938 deaths due to disease during the calendar year 1918, 5,027 were due to pneumonia, as follows:

Lobar pneumonia 601
Broncho-pneumonia 156
Influenzal pneumonia 4,158
Measles pneumonia    112
     Total 5,027

If pneumonia in its various forms could have been eliminated as a cause of death, the death rate of the Navy for disease only would be 1.8 per 1,000 instead of 11.78.

Deaths from pneumonia complicating measles are charged to measles as the primary cause of death. Deaths from pneumonia

--2505--

complicating influenza are charged to influenza as the primary cause of death.

Epidemic influenza with its fatal pulmonary complications so overshadowed all other causes of death that it has been taken up in detail under a separate heading. Chart No. 5 shows the effect of influenza on the admission rate for pneumonia during September, October, and November.

With regard to primary lobar pneumonia, this disease has its greatest prevalence during the months of January, February, March, and April, when exposure to raw, cold, wet, and windy weather is common. (See chart No. 5.) This together with fatigue and other predisposing influences are of great importance in determining development of the disease. During the autumn of 1918 lobar pneumonia was unduly prevalent.

During the first six months of the calendar year 1918, there were 422 deaths from primary lobar pneumonia, with a semiannual death rate of 102 per 100,000. During the first six months of 1919 there were only 82 deaths from primary lobar pneumonia, making a semiannual death rate of 18.3 per 100,000. In this period the bulk of the pneumonias reported were of the influenzal type following in the wake of the great pandemic. It is not unlikely that many of the pneumonias which occurred during the spring of 1918 were in reality largely influenzal in origin, although not recognized as such and therefore considered to be frank lobar pneumonia. Certain it is that streptococci were active invaders, producing a mixed infection of high virulence, as instanced by the large number of deaths from measles pneumonia.

The death rate for pneumonia (lobar and primary bronchial) for the force ashore was 281 per 100,000 while the rate for the same causes for the force afloat was only 78 per 100,000. The admission rates were 55.28 per 1,000 and 8.87 per 1,000, respectively.

There were in all 757 deaths from lobar and primary broncho-pneumonia in the entire Navy during the calendar year 1918. There is thus a death rate of 15.02. (See chart No. 18.) The death rate for civil communities for the year 1917 (figures of 1918 not available) was 149.8 per 100,000.

The following table gives the results of typing in cases of lobar pneumonia:

  Type I. Type II. Type III. Type IV. Total.
League Island 1 2 ------ 10 13
Chelsea 16 8 4 33 61
San Diego 12 16 6 2 36
Hampton Roads 10 9 ------ 17 36
Pelham Bay Park 3 ------ ------ ------ 3
San Francisco 4 1 ------ 1 6
     Total 46 36 10 63 155

--2506--

Chart 18
Chart No. 18.--Annual death rates per 100,000 for certain communicable diseases, entire Navy, calendar years 1909 to 1918.


Source: Annual Report of the Secretary of the Navy, 1919 -- Miscellaneous Reports. (Washington: Government Printing Office, 1919). pp 2414-2506.


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