West Nile Virus Confirmed for the First Time in Bats

Albany, Aug. 30, 2000 – The New York State Department of Health's Wadsworth Laboratory today confirmed West Nile virus infection in three bats which had been previously submitted for testing. Although it is known that the virus can infect small mammals such as cats and dogs, as well as large mammals, the virus never before has been isolated from bats.

The bats, members of the species called "Big Brown bats," were captured in homes in downtown Albany and sent to the Department of Environmental Conservation's Wildlife Pathology Unit (WPU). Because of concerns about possible rabies exposure to the homes' residents, the animals were euthanized and submitted to the State Health Department's Rabies laboratory. Specimens also were submitted by the WPU to the State Health Department for West Nile virus testing.

"This is another clear indication that there are still many more questions than answers about how West Nile virus is establishing itself in the Western hemisphere," State Health Commissioner Antonia C. Novello, M.D., M.P.H., Dr.P.H. said. "Scientists are still learning about the extent of the reservoir for the virus and about the interplay between species. The bottom line, of course, remains the potential threat to human health."

Health officials stress that bats infected with West Nile virus cannot transmit illness to humans. Like birds and mammals, however, they can themselves be infected through mosquito bites. It is unclear what part bats may play in the West Nile virus reservoir. In the Western hemisphere, native species of birds are particularly vulnerable to West Nile, and dead bird sightings often indicate that the virus is present in a specific area.

Unlike birds, bats will not be routinely tested for West Nile infection by the State Health Department. Instead, some of the approximately 3,500 bats that are annually submitted for rabies testing will be retained for West Nile virus testing at a later date, as part of continuing research. Dead bird surveillance and testing, on the other hand, is a very sensitive indicator of West Nile virus and dead bird testing is regularly conducted to assess the scope of West Nile's presence throughout New York State.

As of today, West Nile virus has been confirmed in 49 of the State's 62 counties and it is believed to be endemic throughout New York State. Five human cases have been identified, as well as 412 infections in birds, 171 infected mosquito pools and one equine case.

Most people who are infected with West Nile virus will experience mild symptoms, such as flulike illness, aches and pains, headache and fever. An estimated one percent of individuals will develop encephalitis, which is inflammation of the brain, that can be life threatening. Older individuals are at the highest risk of serious illness.

To protect yourself from West Nile virus choose clothing that will provide maximum protection against biting insects (long pants, long sleeve shirts) if you plan to spend time outdoors, and consider the use of a mosquito repellent containing DEET. It is also important to reduce areas of stagnant water where mosquitoes that can transmit West Nile virus breed. These include containers such as bird baths, discarded tires, flower pots, even children's toys.

For more information about West Nile virus and personal protection measures, check the State Health Department's web site (www.health.state.ny.us). An update on case numbers is posted daily, Monday through Friday, at 4:30 p.m. People who wish to report dead birds should contact the health department in their county of residence, or the New York City Health Department if they reside in New York City.