Know the Facts

More than 37,000 people in the U.S. have been reported with West Nile virus disease since 1999, and of those over 16,000 have been seriously ill and more than 1,500 have died. Many more cases of illness are not reported to CDC. It is estimated that over three million people from every state (except Alaska and Hawaii) have been infected (780,000 became sick) in the 14 years since West Nile virus came to the U.S.

Know Your Risk

All 48 states in the continental U.S. have had human West Nile virus cases. 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.

Where is West Nile virus a problem?

Some states, such as those in highlighted in black on the map below, had greater concentrations of cases of severe disease than others represented in lighter colors in 2013. This can change each year.

Insect repellent: What you need to know

Why take a chance? Prevention is up to you. No one is safe from West Nile virus, but there are steps you can take to help prevent an infection. Avoid the weeks (to months) of aches and fatigue that come with West Nile fever, or the more severe problems of being hospitalized with encephalitis or meningitis (inflammation of the brain and surrounding tissues).

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.