Questions and answers on West Nile virus

          If you watch, listen to or read the news, you've probably heard something about the West Nile virus. This mosquito-borne virus first appeared in the United States three years ago, and it's been back every summer since.

            One of the most important things to know about the West Nile virus is that it remains rare, reports the Centers for Disease Control and Prevention (CDC). No matter where you live, you're very unlikely to catch the virus or become seriously ill from it. Education can reduce your risk even further.

Q: What is West Nile virus?

            A: West Nile virus is a type of flavivirus, which means that it is a disease-causing virus spread by insects. Most of these viruses, including West Nile, are spread by mosquitoes.

            West Nile virus was first identified in a woman in the West Nile district of Uganda in 1937. It has since been found in birds, horses, cats, bats, chipmunks, skunks, squirrels and domestic rabbits.            

Q: How is it spread?

            A: Mosquitoes contract West Nile virus when they bite infected birds. The virus lives in mosquitoes' salivary glands. When an infected mosquito bites a person or an animal, the virus may be passed on.

            Even in areas where the virus has been found, very few mosquitoes are infected.

Q: Where did it come from?

            A: West Nile virus is most common in Africa, West Asia, Europe and the Middle East. It appeared in the Western Hemisphere for the first time in 1999, around New York City.

            Experts don't know how the virus spread to the United States.

Q: Where is it in the United States?

            A: Every summer since 1999, West Nile virus has spread further across the United States. As of late summer 2002, the virus had spread as far west as Texas and the Dakotas. So far, the most human cases have been reported in Louisiana.                                

Q: What are the symptoms?

            A: Most people infected with West Nile virus have either no symptoms or very mild ones. Mild symptoms include fever, headache and body aches. Some people will also have a skin rash and swollen lymph glands.

             Less than 1 percent of people infected with West Nile virus develop West Nile encephalitis, a severe illness caused by swelling in the brain. People older than 50 are at highest risk.

The symptoms of West Nile encephalitis include headache, high fever, neck stiffness, feeling disoriented, coma, tremors, convulsions, muscle weakness and paralysis. Among people who get West Nile encephalitis, 3 percent to 15 percent won't survive.

Q: How can you reduce your risk?

            A: The best way to reduce your risk of West Nile virus infection is to avoid mosquito bites, says the CDC.

            The Environmental Protection Agency (EPA), the American Mosquito Control Association (AMCA) and the CDC offer these suggestions for fighting mosquitoes:

• Empty standing water in old tires, buckets, plastic covers and toys. Mosquitoes lay eggs in standing water.

• Change the water in birdbaths, fountains, wading pools, rain barrels and potted plant trays at least once a week.

• Keep  rain gutters unclogged and remove any standing water on flat roofs. Check around faucets and air conditioner units, and repair leaks or eliminate puddles that remain for several days.

• Check for trapped water in plastic or canvas tarps used to cover boats, pools, etc. Arrange the tarp to drain the water.

• Make sure your window and door screens are "bug tight."

• Replace outdoor lights with yellow "bug" lights.

• As much as possible, stay indoors at dawn, dusk and in the early evening.

• Wear long-sleeved shirts and long pants when you're outside.

• Spray exposed skin and your clothing with mosquito repellent that contains DEET. Follow the label directions and warnings closely. Remember that concentrations of DEET higher than 35 percent provide no additional protection.

Q: Where can I learn more?

            A: For more information on the West Nile virus, visit the CDC's Web site at www.cdc.gov, or contact your local or state health department.

            For more information on mosquito repellents and mosquito control, visit the EPA's Web site at www.epa.gov or the AMCA's Web site at www.mosquito.org.