West Nile virus (WNV) is spread by infected mosquitoes and can cause serious, life-altering and even fatal disease. The easiest and best way to avoid WNV is to prevent mosquito bites since the virus is most often spread through the bite of an infected mosquito.


WNV usually infects birds, but it can be spread to humans by mosquitoes that feed on infected birds and then bite humans. All it takes is one bite from an infected mosquito to get WNV.

Adults are at the highest risk

Although people over age 50 have the highest risk of becoming seriously ill when they get infected with WNV, people of all ages can become ill.

Prevent serious disease

WNV affects the central nervous system and can be very serious. Some people who get infected with WNV develop a paralysis or an inflammation of the brain known as encephalitis. These severe diseases usually require hospitalization. Symptoms may last several weeks and some effects may be permanent.

Symptoms of severe illness include:
□ Severe headache □ High fever
□ Mental confusion □ Stiff neck
□ Muscle weakness □ Coma
□ Tremors (shaking) □ Paralysis

See your healthcare provider if you develop any of these symptoms.

Some people develop a less severe illness called West Nile fever. This illness usually goes away and generally does not require medical treatment. Fortunately, most people who get infected with WNV do not have any ill effects.

To protect yourself and your family from West Nile virus and other mosquito-borne diseases:
  • Avoid mosquito bites
    • Apply insect repellent. DEET (N, N-diethyl-meta-toluamide), picaridin and oil of lemon eucalyptus are effective repellents recommended by the Centers for Disease Control and Prevention (CDC).
    • Apply permethrin to clothing, shoes, bed nets and camping gear but not to skin. With any repellent, follow manufacturer’s instructions.
    • When possible, wear long-sleeves, long pants and socks.
    • Use extra care during peak biting hours which are from dusk to dawn.
  • Mosquito-proof your home
    • Drain or eliminate standing water including items such as plant dishes, toys and buckets.
    • Make sure roof gutters are clean and drain properly.
    • Remove trash, even small items like bottle caps.
    • Install or repair window screens.