An official website of the United States government.

The .gov means it’s official.
Federal government websites always use a .gov or .mil domain. Before sharing sensitive information online, make sure you’re on a .gov or .mil site by inspecting your browser’s address (or “location”) bar.

This site is also protected by an SSL (Secure Sockets Layer) certificate that’s been signed by the U.S. government. The https:// means all transmitted data is encrypted — in other words, any information or browsing history that you provide is transmitted securely.

West Nile Virus

View all resources
West nile virus - DOI, USGS
USGS Wildlife Veterinarian testing for the West Nile Virus USGS, National Wildlife Health Center DOI. USGS. Newsroom.
Scientific Name: 

West Nile virus (ICTV 2018)

Common Name: 

West Nile Virus (WNV)

Native To: 

First discovered in Africa (Roehrig 2013)

Date of U.S. Introduction: 
Means of Introduction: 

Unknown (Roehrig 2013)


Infects birds and mammals (including humans). West Nile virus is primarily an avian pathogen, and is transmitted among birds by ornithophilic (bird-biting) mosquitoes; including the Asian tiger mosquito and other mosquito species (Hayes et al. 2005)

Current U.S. Distribution: 
Most of U.S.

Distribution / Maps / Survey Status

DHHS. Centers for Disease Control and Prevention.

Maps updated to present. Select data by disease (WN), vector (mosquito), state, and year (includes historical data from 2003).

DHHS. Centers for Disease Control and Prevention.
Includes final annual and cumulative maps & data from 1999.



Google. YouTube; Johns Hopkins University. Bloomberg School of Public Health.

Google. YouTube; National Aeronautics and Space Administration.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for West Nile Virus.

UN. World Health Organization.
IUCN. Species Survival Commission. Invasive Species Specialist Group.
Federal Government

USDA. Animal and Plant Health Inspection Service.

DHHS. National Institute of Allergy and Infectious Diseases.

DHHS. Centers for Disease Control and Prevention.

Provides links and resources for State Health Departments, many of which have information about Zika virus and West Nile virus with specific state information.

DOI. USGS. National Wildlife Health Center.
DHHS. Centers for Disease Control and Prevention.
State and Local Government

California Department of Health Services; California Department of Food and Agriculture; Mosquito and Vector Control Association of California; California Vectorborne Disease Surveillance System.

King County Public Health (Washington).

Hawaii State Department of Health. Disease Outbreak Control Division.

New York City Department of Health.

Michigan Department of Natural Resources.

See the complete Wildlife Disease Manual for a list of diseases that are of significance to Michigan wildlife.

Pennsylvania Game Commission.

University of Pennsylvania. School of Veterinary Medicine. Wildlife Futures Program.

Iowa State University. Center for Food Security and Public Health.

Cornell University. Cornell Wildlife Health Lab.

Columbia University. Center for Environmental Research and Conservation.