West Virginia
Infectious Disease Epidemiology Program

Public FAQ:

West Nile Virus

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West Virginia Department of Health and Human Resources Information for the Public Ė West Nile Virus

What is West Nile virus?

West Nile virus is a cause of "encephalitis," which means an inflammation of the brain. It is spread by mosquito bites and can infect people, horses, and birds. For the fourth year in a row, WNV has continued to expand its territory, spreading over much of the United States. Many counties in West Virginia had birds test positive in 2002. Three West Virginia counties also had WNV- positive horses, and three positive human cases were reported from two counties.

What are the symptoms of West Nile virus?

Most people who get West Nile virus infection never have any symptoms at all. A few people have mild symptoms like a fever, headache, and body aches. These people recover without any treatment.

Very few people with West Nile virus infection are sick enough to go to the hospital. These people have a more severe illness with fever, fatigue, confusion, headache, weakness, nausea, vomiting, muscle aches, stiff neck, abdominal pain, and other symptoms. About 10% of individuals hospitalized with West Nile virus die from the infection (this equates to < 0.1% of total infections).

Who is most at risk for West Nile virus?

People over age 50 are most at risk. People who go out-of-doors in summer without taking precautions against mosquitoes may also be at higher risk.

How is West Nile virus spread?

The principal route of West Nile virus infection in horses, humans, and birds is through the bite of an infected mosquito. Mosquitoes get infected if they bite infected birds. After about 10 to 14 days, infected mosquitoes can spread West Nile virus to humans and animals. The virus is spread to humans by mosquito bites. The virus cannot be spread directly from one person to another.

Five additional routes of infection have become apparent during the 2002 West Nile season. It is important to note that these other methods of transmission represent a very small proportion of cases. New modes of transmission are via: Transplantation, Transfusion, Breastfeeding, Transplacental and Occupational exposures (mostly laboratory workers). (More information may be found on the CDCís website at: http://www.cdc.gov/ncidod/dvbid/westnile/clinical_guidance.htm)


How can I protect my family from West Nile virus?

Get rid of mosquito breeding sites. These include old tires, or any containers near your house that can collect water. Fill in ditches or make sure that the water drains freely.

Wear long-sleeved shirts and long pants whenever you are outdoors.

Use bug repellent with DEET and follow package directions carefully. Apply sparingly to children and wash them with soap and water when they come indoors. Avoid application to the hands and face of young children.

Make sure doors and screens are "bug tight."

Contact your doctor if you feel ill.


State of West Virginia (WV)
West Virginia Department of Health and Human Resources (DHHR)
Bureau for Public Health (BPH)
Office of Epidemiology and Health Promotion (OEHP)
Division of Surveillance and Disease Control (DSDC)
Infectious Disease Epidemiology Program (IDEP)

A-Z Listing of West Virginia's Reportable Diseases

This FAQ was last updated May 2003.
If you have questions or comments about the West Virginia Division of Surveillance and Disease Control, please direct them to Loretta Haddy at Loretta.E.Haddy@wv.gov.
If you have questions or comments about this Web page, please direct them to Betty Jo Tyler at Betty.J.Tyler@wv.gov.