What Is It?

West Nile is a virus that can cause illnesses or fatal encephalitis (also called inflammation of the brain) in people, horses, many types of birds and possibly other animals. It spreads through the bites of infected mosquitoes, but there is no evidence to suggest that it can be spread from person to person or from animal to person.

Where Did It Come From?

The virus has been commonly found in humans and birds and other animals in Africa, Eastern Europe, West Asia and the Middle East. But it wasn't reported in the Western Hemisphere until 1999. It is not known from where the U.S. virus originated, but it is most closely related to strains found in the Middle East.

How Prevalent Is It?

In 1999, 62 severe cases of West Nile encephalitis was reported in humans in the New York area, including seven deaths. In 2000, 21 cases were reported, including two deaths in the New York City area. In 2001, there were 66 human cases of severe disease and 9 deaths. No reliable estimates are available for the number of cases of West Nile encephalitis that occur worldwide.

Symptoms

If a human is infected with the virus, it multiplies in the person's blood system and crosses the blood-brain barrier to reach the brain. Symptoms include fever, headache and body aches, occasionally with skin rash and swollen lymph glands. There is no vaccine against West Nile encephalitis, although several companies are working to develop one. Less than 1 percent of those infected with West Nile virus will develop severe illness.

Protect Yourself

Cases of human illness from West Nile virus have been rare, and the odds of becoming ill from a mosquito bite are low. Reduce your chances further by avoiding mosquito bites:

Eliminate standing water from around your home.
Always wear repellent, even on thin clothing.
Wear long-sleeved shirts and long pants whenever you are outdoors.
Stay indoors during peak mosquito hours (dawn, dusk and early evening).
Repellents may irritate the eyes and mouth, so avoid applying repellent to the hands of children.

If You Find A Dead Bird ...

Many people now know that the virus can kill many types of birds and that dead birds in your neighborhood may mean that mosquitoes carrying the virus are in the area. Most of the time, the bird's death was not caused by the virus. However, if you see a dead bird, you should tell your local or state health department. They may choose to pick up and test the bird for the virus.

Source: Centers for Disease Control and Prevention

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