USGS is coordinating a multi-state surveillance network to detect and monitor the movement of the West Nile Virus in birds, which can contract the disease from mosquitoes.

During the fall of 1999, West Nile virus, a mosquito-borne disease never previously reported in the Western hemisphere, caused encephalitis in people in the New York City area. Birds are the natural hosts for this virus, which can be transmitted from infected birds to humans and other animals through bites of infected mosquitoes.

USGS scientists and other investigators diagnosed West Nile virus in birds from New York, New Jersey, Connecticut, and Maryland. USGS alerted State and Federal wildlife agencies and dispatched a team of wildlife health specialists from the National Wildlife Health Center in Madison, WI, to New York to determine the bird species involved and the geographic distribution of the virus.

Wild bird surveillance will be used for early detection of the virus. Crow samples are especially important because crows appear to be highly sensitive to the virus. Crows can act as sentinels for local transmission of the disease since they normally travel less than 200 miles and generally do not migrate. Infected crows can also help State and local health departments determine the risk to humans.

USGS is working with the Centers for Disease Control, U.S. Departments of Agriculture and Defense, U.S. Fish and Wildlife Service, National Park Service, and State public health and natural resource agencies on surveillance networks to track the disease. Suspect wild birds found dead in the multi-state surveillance area are being examined and tested at the USGS biological containment facility in Madison. This effort will include all the states along the Eastern seaboard and the Gulf Coast.

USGS, in partnership with USDA, is conducting active surveillance of resident wild bird species to identify local areas of West Nile virus activity. To date nearly 1200 blood specimens have been received from 10 states for testing.

USGS is conducting laboratory and field research to determine the susceptibility and virulence of West Nile virus in native bird species. Laboratory studies with American crows are in progress at the USGS biological containment facility.

Work will continue to focus on collecting both information and samples to help determine which wildlife species are involved, the distribution of the virus in bird populations, and if the range of the virus is expanding beyond the currently reported sites.

For more information about West Nile virus and other wildlife diseases, contact Dr. Robert McLean at the USGS National Wildlife Health Center; 608-270-2401. To learn more about USGS research programs and activities, visit our main web site at http://www.usgs.gov.