West Nile Virus
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West Nile virus (WNV) is most often spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Most people who become infected will not get sick. About 1 in 5 people who get infected will develop symptoms: fever, headache, body aches, joint pain, nausea or rash. Less than 1% of infected people will develop serious neurologic illness. For people who develop severe symptoms, recovery may take weeks to months. Some people will not recover. About 10% of people who develop neurologic illness will die. Symptoms begin between 3 and 14 days after being bitten by an infected mosquito.
Quiz
Key Facts
- West Nile virus is spread to people by infected mosquitoes.
- You are at highest risk for getting infected with West Nile virus from June-September.
- Outbreaks occur each summer, but we cannot predict how many cases will occur or where.
- 1 in 5 people infected with West Nile virus will develop symptoms like fever, headache, body aches, joint pain, nausea or a rash.
- There is no vaccine available to protect you or your family from getting infected with West Nile virus.
Media
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Photomicrograph of brain tissue from a person with West Nile encephalitis. Cells and tissues in red are positive for West Nile virus.
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The best way to prevent infection with WNV is to prevent mosquito bites. Choose an insect repellent with one of the following active ingredients: DEET, picaridin, oil of lemon eucalyptus or IR3535.
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Keep mosquitoes from laying eggs in and around your home. Once a week, empty, turn over, cover, or throw out any item that holds water, such as tires, buckets, planters, toys, pools, birdbaths, or trash containers.
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When using insect repellent on your child, apply it to your own hands and then rub them on your child. Avoid children's eyes and mouth and use it sparingly around their ears. Do not apply repellent to children's hands. (Children tend to put their hands in their mouths.
Prevention Tips
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Use insect repellent. Repellents containing DEET, picaridin, oil of lemon eucalyptus and IR3535 provide hours of lasting protection. Always follow the label instructions.
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Wear long-sleeved shirts and long pants.
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Keep mosquitoes out of your home. Use screens on windows and doors. Repair holes in screens to keep mosquitoes outside.
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Once a week, empty and scrub, turn over, cover, or throw out any item that holds water, such as tires, buckets, planters, toys, pools, birdbaths, or trash containers. Check inside and outside your home
- Page last reviewed: March 3, 2016
- Page last updated: March 3, 2016
- Content source:
- Centers for Disease Control and Prevention
- Page maintained by: Office of Associate Director of Communication, Division of Public Affairs