It also might not be so apparent, he said, because animals have had generations to build immunity to the virus. And if we've got the virus in these two, it's entirely logical that we're going to find it in a number of other mammalian species in the Western Hemisphere. The cause could be any number of things, such as pesticides or harsh weather conditions. Bats are especially difficult to test because of precautions against rabies. But most laboratories are focused solely on testing wild birds as part of the multistate surveillance system, and cannot spare the time or limited resources looking at how West Nile virus may be affecting other animal species.
Stone wonders whether infected bats are contributing to the spread of the virus in New York.
If bats are, in fact, viral reservoirs, then on the basis of the migratory patterns of various bat species, the wildlife pathologist sees the potential for West Nile virus to penetrate farther into the United States, and into Central and South America and Canada. What the future holds and additional investigations will uncover are uncertain. It is hoped that the virus will be contained, the damage to the ecosystem minimal, and that wildlife will eventually build immunity. Vaccines for horses and people, according to Stone, could come along within the next five to 10-years. Dr. Eidson maintains that veterinarians are key to combating West Nile virus.