U.S. National Library of MedicineNational Institutes of Health
Skip navigation
MedlinePlus Trusted Health Information for You MedlinePlus Trusted Health Information for You MedlinePlus Trusted Health Information for You
Contact Us FAQs Site Map About MedelinePlus
español

Other Health Topics:
Printer-friendly version E-mail this page to a friend
Photograph of a mosquito on human skin

  • Related Topics

  • Go Local

    • Services and providers for West Nile Virus in the U.S.

  • National Institutes of Health

  • Languages

Also called: WNV

West Nile virus (WNV) is an infectious disease that first appeared in the United States in 1999. Infected mosquitoes spread the virus that causes it. People who contract WNV usually have no symptoms or mild symptoms. Those with symptoms may have a fever, headache, body aches, skin rash or swollen lymph glands.

If West Nile virus enters the brain, however, it can be deadly. It may cause inflammation of the brain, called encephalitis, or inflammation of the tissue that surrounds the brain and spinal cord, called meningitis.

Older people are most at risk. There are no specific vaccines or treatments for human WNV disease. The easiest and best way to avoid WNV is to prevent mosquito bites:

  • Use insect repellent
  • Get rid of mosquito breeding sites by emptying standing water from flower pots, buckets or barrels
  • Stay indoors between dusk and dawn, when mosquitoes are most active
  • Use screens on windows to keep mosquitoes out

National Institute of Allergy and Infectious Diseases

Start Here

Home | Health Topics | Drugs & Supplements | Encyclopedia | Dictionary | News | Directories | Other Resources
Disclaimers | Copyright | Privacy | Accessibility | Quality Guidelines
U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894
National Institutes of Health | Department of Health & Human Services 		Date last updated: 16 January 2009
Topic last reviewed: 08 December 2008