At 08:27 AM 9/21/1998 +1000, you wrote:
>Trouble with viruses as agents of biological control is that they are never
>100% efficient; they are often 99%, but then what you are doing is selecting
>the 1% of the population with a natural resistance to the disease, which can
>then breed up again afterwards. With small populations you could 'send the
>marines in' afterwards to 'mop up pockets of resistance', but with a
>widespread pest like rabbits there would be no chance of that, even if the
>virus is much more effective than calici (spelling?) has been.
>
>Also the chance of getting a family-specific virus in birds would be rather
>small I should think.
>
>John Leonard
Agreed,
Viral infections might also confer a biological advantage of one species
over another. Newcastle disease is a good example. When one carrier
species of waterfowl spreads a highly pathogenic strain of the infection to
a dense population of a susceptible species the latter can suffer
dramatically but usually (as John points out) only temporarily. Infectious
diseases can be potent weapons for colonisation by both man and animals.
-----------------------------------------
Shane Raidal BVSc PhD MACVSc
Lecturer in Veterinary Pathology
Division of Veterinary and Biomedical Sciences
Murdoch University
South Street Murdoch WA 6150
Australia
ph: +61 8 9360 2418
fx: +61 8 9310 4144
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