West Nile Virus


West Nile virus is a disease transmitted to humans and animals through the bite of an infected mosquito. Mosquitoes become infected after feeding on infected birds.

West Nile virus is common in birds, humans and other animals in Africa, Australia, Eastern Europe, west Asia and the Middle East.

It was first detected in North America in 1999, and has since spread across the continental United States and Canada.


Most people infected with West Nile virus have no symptoms. About one in five people infected becomes ill within two to 14 days with symptoms including fever, headache, joint pain, muscle pain, and occasionally nausea and vomiting. Often they experience sensitivity to light and inflammation of the eyelids. Some may have a rash.

The risk of serious illness is low. Less than one percent of people infected develop a potentially fatal swelling of the brain, known as encephalitis.


There is no specific cure for West Nile virus. In mild cases, you should use the same remedies you would for other viruses, such as the flu: drinking plenty of water and fluids, resting in bed, and taking medication such as ibuprofen or acetaminophen to relieve fever and discomfort. In more severe cases treatment may include hospitalization, respiratory support and intravenous therapy.

Anyone experiencing severe or unusual headaches should see a doctor as soon as possible. Also, anyone who has been in an area where the virus has been identified and who experiences high fever, muscle weakness, confusion or severe headaches should see a doctor immediately.


West Nile virus cannot be passed from person to person. The only way to get the virus is from the bite of an infected mosquito.

The virus actually starts with a bird, usually a crow. It spreads when a mosquito bites a bird that has the virus in their blood. The mosquito then can spread the virus to other birds, animals or people, when it bites during feeding. In areas where the virus has been identified, very few, much less than 1%, of the mosquitoes are infected.


A key step for prevention is reducing the breeding grounds for mosquitoes. Be sure to empty any and all containers that hold standing water, and keep them emptied.

You can reduce the possibility of this West Nile virus spreading by taking a few other simple steps to prevent mosquito bites:

  • Apply insect repellent containing DEET, picaridin, oil of lemon, eucalyptus, or IR 3535 according to label instructions. Repellents help keep mosquitoes from biting.
  • Wear clothing that reduces the risk of skin exposure.
  • Exposure to mosquitoes is most common during the early morning. Some species bite during the day, especially in wooded or other shaded areas. Avoid exposure during these times and in these areas. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes.
  • Eliminate all sources of standing water on your property, including flowerpots, old car tires, rain gutters and pet bowls.

You also can help DHEC track West Nile virus by submitting dead blue jays, crows, house sparrows, and house finches for testing.

DHEC accepts submission of birds from March 15th until November 30th every year.

Instructions on how to safely pick up and transport a bird to the closest DHEC local county health department or Environmental Quality Control office is available online at scdhec.gov/birdtesting .

References and Additional Information



Health Infectious Diseases West Nile Virus