Subject: Re: insect viruses

From: [email-masked] (Adam S Jones)
Date: 23 May 1995 16:51:15 GMT

[email-masked] wrote:

: I heard recently that there is a company interested in using insect
: viruses as "insecticides."   Does anyone know what viruses and if they
: could be dangerous to other wildlife? 

	I can think of three groups: the Baculoviridae, the 
Chloriridovirus and a Salivary Gland Hyperplasia virus. The first is a 
virus family specific to arthropods, and can be subdivided (depending on 
your terminology) into the granulosis viruses (GVs), the non-occluded 
viruses (NOVs), and the Nuclear Polyhedrosis Viruses (NPVs). NPVs are being 
heavily researched, and there have been several field trials on various 
pest insects; they are most likely what the company is interested in.
	The Chloriridovirus is a candidate for mosquito control -- it 
turns the insect an iridescent green or purple from what I understand. 
Salivary Gland Hyperplasia has been found in house flies and (I think) 
horse flies. Though these last two viruses are insect specific, they 
don't hold much promise for pest control for various reasons.
	Anybody know of any others?
							Adam

---

From: Franck Brunel <[email-masked]>
Date: Thu, 25 May 1995 03:40:40 GMT

DC-
				There are many difficulties in trying to employ viruses to eliminate 
pests, similar to the problems with using antibiotics for killing 
bacteria. Some segment of the population will probably survive and then 
expand and thus you are back where you started. If you are successful 
this is not necessarily a good thing, because the 'pest' to you may be 
serving an important ecological function that is now going to be hurt 
(see the millipede discussion elsewhere in the group!). Lastly, if one 
assumes that you can totally eliminate the pest without direct 
consequences to the environment, you have now created a great big niche 
for some other, potentially more annoying pest to fill. There are 
examples of areas in the third world in which insect control via DDT was 
very successful in eliminating disease-carrying mosquitoes only to be 
replaced by similar or worse species once we realized how bad DDT really 
was. It seems that the eradication only served to make things worse 
later!
				
				A separate issue with viruses, as well as any quickly evolving 
(relative to us) organisms, is that of recombination to form deadlier 
forms. By introducing a virus that is 'specific' for house flies into 
the environment, you run the risk of it coinfecting a fly with some 
nonspecific virus and now having an insect plague on your hands. I 
mention this because there is currently a debate in the AIDS field 
regarding the use of a live HIV vaccine; some virologists fear that 
potential recombination inside humans with other viruses may create a 
bigger problem than we have now (and the one we have now is 
astonishing!). Just imagine an airborne form of HIV and you can see what 
I mean!

						-Sean
--

Sean Stevens: The Rockefeller University, New York, USA. 
[email-masked]