West Nile Virus
What Is West Nile Virus?
West Nile virus is a mosquito-borne virus that can cause encephalitis (an inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord) in humans and other animals. The virus is named after the West Nile region of Uganda where it was first isolated in 1937. The virus appeared for the first time in the United States during a 1999 outbreak in New York that killed seven people. Most people bitten by a mosquito infected with West Nile virus do not get sick.
How Is West Nile Virus Spread?
West Nile virus is spread to humans, birds and other animals through the bite of an infected mosquito. A mosquito becomes infected by biting a bird that is carrying the virus. West Nile virus is not spread from person to person, and no evidence indicates the virus can be spread directly from birds to humans.
What Are My Chances of Getting West Nile Virus?
In areas where West Nile virus has been detected, only a small proportion of mosquitoes are likely to be infected. Most people bitten by an infected mosquito do not become sick.
- 1 in 300 people bitten by an infected mosquito get sick.
- 1 in 100-150 who get sick become seriously ill.
- 3 to 15% of those seriously ill die.
What are the symptoms?
The symptoms generally appear 3 to 6 days after exposure. People over age 50 are at greater risk of severe illness.
Milder symptoms include:
- slight fever
- body aches
- swollen glands
- sometimes a skin rash
Severe symptoms include:
- high fever
- intense headache
- stiff neck
What Do I Do If I Think I Have West Nile Virus?
If you are bitten by a mosquito, you don't need to see a doctor. Most people who suffer a mild illness due to West Nile virus recover, and no treatment is necessary. Only supportive treatment is available for more serious cases. Testing for West Nile virus in people involves a blood or spinal fluid test that can take several weeks to confirm. No vaccine exists at this time for West Nile virus infection in humans.
Protecting Your Health
The Virginia Department of Health, along with multiple other agencies, is monitoring for mosquito-borne viruses in birds, mosquitoes, horses and humans. The information collected is used to advise local authorities and the public about the potential threat of West Nile virus in Virginia.
Reporting Dead Birds
The public can help state officials monitor for the virus by reporting all dead birds to their local Health Department. The state will compile data on the number of dead birds reported. Selected crows, blue jays and raptors (i.e. hawks, falcons or owls) will be tested for the virus. Birds must be tested within 24 hours of death before they become too decomposed. Sunken eyes and the presence of fly larvae (maggots) are good indicators that the bird has been dead too long.