West Nile Virus (WNV) special powers of a supervillain

So far it is known to be able to infect 200 different species of at least 3 major classes of Vertebrates -Birds, Reptiles and Mammals - that is, it lacks host specificity.

The virus can be transmitted via methods other than a mosquito bite.

Infected life cycle
The virus can be directly transmitted from the adult mosquito to it's eggs. Newly hatched mosquitoes are born infected. This limits the usefulness of insecticides that only kill the adult population and not the aquatic larvae.

West Nile Virus can spread all year round, even in higher latitudes. There is a winter host, whose identity is uncertain (as of December 2002).So it is able to overwinter, each year the summer eruption of the epidemic occurs earlier.

WMV uses a diverse range of Mosquito carriers. Unlike most mosquito borne diseases, West Nile Virus doesn't limit itself a specific mosquito host. It appears to be carried by almost any genera of mosquito. Therefore West Nile Virus is not limited by a single vector's host range.

West Nile Virus has the potential to mix genetic material with a relative virus that causes St. Louis encephalitis. This could occur if an animal host was co-infected by both viral strains. The formation of a hybrid virus would spread a variant disease with unforseeable symptoms.

People worry mostly about diseases from an anthropocentric perspective. Alternatively some take a more positive view of epidemic diseases as one form of human population control. For example, that HIV is bio control for human overpopulation. WNV is killing people. But that is half the story. It has the potential to kill endangered species and other wildlife with varying levels of destructiveness. West Nile Virus spreads uncontrolled by barriers of species, diversity or distance.

Likely, as with many other pathogens, it will attenuate. For example, like the Myxoma virus and the rabbits humans set it as plague upon, the host populations will gain tolerance and survive, as did the rabbits. West Nile Virus is not Captain trips, But it has the potential to snuff out marginal species. A robust population needs two legs to stands on - numbers and genetic diversity. The virus shakes the rug of life. Attacking its backbone.

Inspiration and factual background
West Nile's Widening Toll Impact on North American Wildlife Far Worse Than on Humans By Rick Weiss Washington Post Staff Writer Saturday 28 December 2002; Page A01