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Prevent Mosquito Bites

Woman spraying insect repellent on child's legsStay healthy this summer. Protect yourself and your loved ones from mosquito bites that cause West Nile virus infection.

Mosquito bites can be more than just itchy and annoying. They can cause you to get sick. The most effective way to avoid West Nile virus disease is to prevent mosquito bites. Be aware of the West Nile virus activity in your area and take action to protect yourself and your family.

Know the facts

Almost 40,000 people in the U.S. have been reported with West Nile virus disease since 1999, and of those over 17,000 have been seriously ill and more than 1600 have died. Many more cases of illness are not reported to CDC.

Photo: Mosquito biting personKnow your risk

Anyone living in an area where West Nile virus is present in mosquitoes can get infected. West Nile virus has been detected in all lower 48 states (not in Hawaii or Alaska). Outbreaks have occurred every summer since 1999. Though anyone can get infected with West Nile virus, there are people at higher risk for severe disease. People over the age of 50 are at higher risk for encephalitis. The reasons one person becomes severely ill and another doesn't aren't entirely known.

West Nile virus (WNV) neuroinvasive disease incidence reported to ArboNET, by state, United States, 2013

Map: Final West Nile virus (WNV) Neuroinvasive Diease Incidence reported to ArboNET by state, United States, 2011

View map of infections occurring in 2013 [139 KB].
See also detailed case counts by state [117 KB].

Where is West Nile virus a problem?

Some states, such as those in highlighted in black on the map to the right, had greater concentrations of cases of severe disease than others represented in lighter colors in 2013. This can change each year. Some areas of the U.S. are affected by other viruses such as La Crosse, eastern equine encephalitis, St. Louis encephalitis, Powassan, or dengue viruses.

Insect repellent: What you need to know

No one is safe from West Nile virus, but there are steps you can take to help prevent West Nile virus infection.

  1. Apply insect repellent on exposed skin and clothing when you go outdoors. Use an Environmental Protection Agency (EPA)-registered insect repellent. Permethrin sprayed on clothing provides protection through several washes. Don’t spray repellent on skin under clothing and don’t use permethrin on skin.
  2. Cover up! Wear long sleeve shirts and long pants and socks while outdoors to prevent mosquito bites.
  3. Avoid mosquitoes. The mosquitoes that spread West Nile virus bite between dusk and dawn. Limit the amount of time you spend outdoors during these hours. If you are outside, be sure to wear repellent and protective clothing.
  4. Support your local community mosquito control programs. Mosquito control activities are most often handled at the local level, such as through county or city government. The type of mosquito control methods used by a program depends on the time of year, the type of mosquitoes to be controlled, and the habitats where the mosquitoes live. Methods can include eliminating mosquito larval habitats, applying insecticides to kill mosquito larvae, or spraying insecticides from trucks or aircraft to kill adult mosquitoes. Your local mosquito control program can provide information about the type of products being used in your area. Check with your local health department for more information.

Photo: Child, pet and mosquitoe repellentWhat insect repellent should I use?

CDC recommends a variety of safe and effective repellents for you and your family. There are those that can protect you for a short while in the backyard or a long while in the woods.

Look for these active ingredients recommended by CDC and EPA:

  • DEET
  • picaridin
  • IR3535
  • plant-based oil of lemon eucalyptus

Pick your favorite insect repellent and use it whenever you go outside!

All contain an EPA-registered active ingredient and have been evaluated for efficacy and safety. EPA has a long listing of every registered repellent brand in the U.S. There are safe and effective repellents for every budget, age and preference.

Know the symptoms of West Nile infection

No symptoms in most people.
Most people (70-80%) who become infected with West Nile virus do not develop any symptoms.

Fever in some people.
About 1 in 5 people who are infected will develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.

Severe symptoms in a few people.
Less than 1% of people who are infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). The symptoms of neurologic illness can include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. See your healthcare professional if you think you have the symptoms of West Nile infection.

Additional West Nile virus Resources:
For more WNV information, see CDC's West Nile virus site or EPA's registered repellent information.

The American Academy of Microbiology (AAM) published a comprehensive report in 2013 called West Nile virus FAQ [1.6 MB].

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