West Nile virus is a virus commonly found in Africa, West Asia, and the Middle East. It is not known how long it has been in the United States, but the Centers for Disease Control and Prevention (CDC) believe the virus probably has been in the eastern United States since early summer 1999. It is closely related to St. Louis encephalitis virus found in the United States. The virus can infect humans, birds, mosquitoes, horses, and some other animals.
How can I reduce my risk of getting West Nile virus?
Preventing mosquito bites is the best way to avoid becoming infected with the West Nile virus. Protect yourself from the West Nile virus with these four tips:
1. Use an approved insect repellent every time you go outside. Approved repellents are those that contain DEET, picaridin or oil of lemon eucalyptus. Follow the instructions on the label.
2. Regularly drain standing water, including water that collects in empty cans, tires, buckets, clogged rain gutters and saucers under potted plants. Mosquitoes breed in stagnant water.
3. Wear long sleeves and pants at dawn and dusk when mosquitoes are most active.
4. Use air conditioning or make sure there are screens on all doors and windows to keep mosquitoes from entering the home.
What are the symptoms?
Most people infected with West Nile virus will not have any signs of illness. Twenty percent of people who become infected will have mild symptoms such as fever, headache, body aches, and occasionally a skin rash on the trunk of the body and swollen lymph glands.
The symptoms of severe infection (West Nile neuroinvasive disease) include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Only about one out of 150 people infected with West Nile virus will develop this more severe form of the disease.
The incubation period of West Nile virus in humans is three to 14 days. Symptoms of mild disease may last a few days. Symptoms of severe disease may last several weeks, although neurological effects may be permanent. Rarely, death can occur.
How is it spread?
West Nile virus is spread by the bite of an infected mosquito and can infect people, horses, many types of birds, and some other animals. There is no evidence that West Nile virus can be spread from person to person or from animal to person.
Who is at risk for West Nile virus?
People older than 50 have the highest risk of severe disease, and people with weakened immune systems are at an increased risk for West Nile virus. Department of State Health Services • Toll Free 1-888-963-7111 • TDD 1-800-735-2989.