West Nile virus (WNV) is a potentially serious illness. Experts believe West Nile Virus is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. This fact sheet contains important information that can help you recognize and prevent West Nile virus. The rate of fatality is 3-15% among those who develop the disease. WNV encephalitis primarily affects persons over 50 years of age. Those with a compromised immune system may also be more susceptible to acquiring encephalitis. Currently no approved human vaccine is available for WNV.
The easiest and best way to avoid West Nile Virus is to prevent mosquito bites.
West Nile Virus affects the central nervous system. Symptoms vary.
People typically develop symptoms between 3 and 14 days after they are bitten by the infected mosquito.
There is no specific treatment for West Nile Virus infection. In cases with milder symptoms, people experience symptoms such as fever and aches that pass on their own. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, help with breathing and nursing care.
Milder West Nile Virus illness improves on its own, and people do not necessarily need to seek medical attention for this infection though they may choose to do so. If you develop symptoms of severe West Nile Virus illness, such as unusually severe headaches or confusion, seek medical attention immediately. Severe West Nile Virus illness usually requires hospitalization. Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be West Nile Virus.
People over 50 at higher risk to get sick. People over the age of 50 are more likely to develop serious symptoms of West Nile Virus if they do get sick and should take special care to avoid mosquito bites.
Being outside means you're at risk. The more time you're outdoors, the more time you could be bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing.
Risk through medical procedures is very low. All donated blood is checked for West Nile Virus before being used. The risk of getting West Nile Virus through blood transfusions and organ transplants is very small, and should not prevent people who need surgery from having it. If you have concerns, talk to your doctor.
Pregnancy and nursing do not increase risk of becoming infected with West Nile Virus. The risk that West Nile Virus may present to a fetus or an infant infected through breastmilk is still being evaluated. Talk with your care provider is you have concerns.
If you find a dead bird: Don't handle the body with your bare hands. Contact your local health department for instructions on reporting and disposing of the body. Click here for information about reporting birds in your state.
For more information call the Center for Disease Control (the CDC) public response hotline
at (888) 246-2675 (English), (888) 246-2857 (Espaņol), or (866) 874-2646 (TTY)
There are about 200 different species of mosquitoes in the United States, all of which live in specific habitats, exhibit unique behaviors and bite different types of animals. Click here for a page on how to control mosquitoes in your yard and neighborhood.
The following bird identification pages illustrate the most common bird species affected by West Nile virus. To date the species most affected are: 1) American Crows 2) Western Scrub-Jays 3) Yellow-Billed Magpies and 4) Steller's Jays.
Corvids (Crows, Ravens, Magpies, and Jays)...............................Click Here
Raptors (Birds of Prey).................................................................Click Here
Sparrows (House Sparrow, White-Crowned Sparrow, etc.).........Click Here
Finches (Lesser Goldfinch, House Finch, etc.)...............................Click Here