Assessing the Effects of WNV throughout North America

Since the detection of West Nile virus (WNV) in 1999 in the New York City area, it has rapidly spread across the continent, with virus activity detected in almost all of the continental United States.

The National Wildlife Health Center (NWHC) quickly contributed to the WNV surveillance effort, offering diagnostic services to state and federal public health agencies, as well as specialized expertise, since 1999. The WNV surveillance program works with state and local public health agencies to monitor birds for the presence of the virus nationwide, while investigating local and regional die-offs potentially due to WNV. The NWHC has received over 8,500 carcasses for testing from 34 States plus the District of Columbia, the Department of Defense, as well as the Department of Interior. These submissions represent over 200 species of birds, mammals, and even amphibians. Of these, 16.6 percent have tested positive for WNV or WNV antibodies.

Surveillance, die-off investigations, and experimental studies conducted by USGS have allowed scientists to explore and understand not only the public health importance of the virus’ arrival in the Western Hemisphere, but also its potential effect in wild bird populations.

For more information, download our most recent information sheet on WNV (1.39 MB), or contact Emi Saito, 608-270-2400.