Health-Related Links -- West Nile Virus

What is West Nile virus?

West Nile virus is a a virus that is commonly found in Africa, Europe, Asia, and the Middle East. The virus appeared in the United States in 1999. In most people, the virus is asymptomatic or causes a mild disease that lasts several days. Encephalitis, inflammation and swelling of the brain, may occur rarely in some persons who are infected with the virus. Encephalitis usually occurs in late summer or early fall and is a more severe disease.

How is the virus spread?

West Nile virus is spread by infected mosquitos. In areas where West Nile virus is present only a few mosquitos become infected. Birds, horses, and other animals can become infected as well as humans. The disease has not been found to spread from person to person.

What are the signs and symptoms of West Nile virus?

Most people infected with the virus will not become ill. About one fifth of infected people will develop a mild illness with fever, headache, bodyaches, and possibly a rash. Symptoms usually appear 3-14 days after being bitten by a infected mosquito. Rarely, less than one person out of a hundred infected people, will develop severe illness with high fever, neck stiffness, confusion, seizures, and possible paralysis.

How is West Nile virus diagnosed?

Diagnosis is made by your medical history and blood tests.

Can West Nile virus be treated?

There is no specific treatment for the virus. Persons with encephalitis require hospitalization for supportive care.

How can I reduce my chances of becoming infected?

Decrease the number of mosquitos in your yard by:

  1. emptying items that collect water, such as buckets, pet dishes, birdbaths, pool covers,etc.
  2. spray insecticide around bushes and under your house
  3. clean out debris from your yard

Protect against mosquito bites by:

  1. apply an insect repellent containing DEET to your uncovered skin
  2. apply an insect repellent containing DEET to your clothing
  3. cover as much of your body as possible, wear long pants and long sleeves
  4. avoid going outside in the early morning & evening when more mosquitos are out
  5. put screens on all doors and windows

For further information contact:
800–CDC–INFO (800-232-4636), 888–232–6348 (TTY),
Or visit  or

Centers for Disease Control and Prevention
1600 Clifton Rd., NE
Atlanta, GA 30333
Phone: (404) 639-3311