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West Nile Virus

Aedes albopictus mosquito

West Nile virus (WNV) is most often spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. In North America, cases of WNV occur during mosquito season, which starts in the summer and continues through fall. WNV cases have been reported in all of the continental United States. There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not have symptoms. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness. You can reduce your risk of WNV by using insect repellent and wearing long-sleeved shirts and long pants to prevent mosquito bites.

Quiz

Key Facts

  • WNV is the most common virus spread by mosquitoes in the continental United States.
  • There are no vaccines to prevent or medications to treat WNV in people.
  • Most people infected with WNV do not have symptoms.
  • About 1 in 5 people who are infected develop a fever and other symptoms.
  • About 1 out of 150 infected people develop a serious, sometimes fatal, illness.
  • You can reduce your risk of WNV by using insect repellent and wearing long-sleeved shirts and long pants to prevent mosquito bites

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Prevention Tips

  • Use Environmental Protection Agency (EPA)-registered insect repellents with one of the active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone.
  • Cover up: wear long-sleeved shirts and long pants.
  • Keep mosquitoes out of your home. Use screens on windows and doors. Repair holes in screens to keep mosquitoes outside. Use air conditioning if available.
  • 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.

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