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.

You are here

West Nile Virus

Back to top
West nile virus - DOI, USGS
Scientific Name:
West Nile virus (ICTV 2018)
Common Name:
West Nile Virus (WNV)
USGS Wildlife Veterinarian testing for the West Nile Virus USGS, National Wildlife Health Center DOI. USGS. Newsroom.
Native To:
First discovered in Africa (Campbell et al. 2002)
Date of U.S. Introduction:
Means of Introduction:
Accidental (Calisher 2000)
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.


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.

North Central Integrated Pest Management Center.

See also: Pest Alerts for more resources

Federal Government

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.


Iowa State University. Center for Food Security and Public Health.
University of Florida. Institute of Food and Agricultural Sciences Extension.
Electronic Data Information Source Publication #ENY-642
Columbia University. Center for Environmental Research and Conservation.