West Nile rapidly heading west-Health officials predict virus may hit California by next year


July 29, 2002  West Nile virus is sickening people far earlier this summer than usual, and is spreading so quickly — it’s hit 34 states, as far west as South Dakota — that health officials believe it will reach California this year or next.

NOBODY KNOWS how bad the mosquito-borne illness will get — although a rapidly growing outbreak among 32 people in Louisiana began a month earlier than West Nile has ever struck in this country, a big worry. But it’s clear the virus first detected in New York City a mere three years ago has become a permanent summertime threat in most states.
       Yet it’s fairly easy to prevent: Spray on DEET-containing mosquito repellent when you go outdoors, and don’t let puddles collect in flower pots, wading pools or other spots where mosquitoes can breed. One specialist equates the safety steps to the routine of buckling a seat belt before driving.
       “That’s the level of worry people should have,” says Dr. Lyle Petersen of the Centers for Disease Control and Prevention. “You should be concerned enough about it to do something but not have it change your whole lifestyle.”
       West Nile virus has struck other countries for decades, from the tip of Africa up to Europe and throughout Asia, so its move here probably was inevitable. The CDC has confirmed 161 U.S. cases, including 18 deaths, since the first Americans were diagnosed in 1999.
       Officials are investigating if West Nile just killed two people in Louisiana. In addition to 32 West Nile-caused encephalitis cases there, a Mississippian is sick and health officials are investigating 10 similarly ill Texans.
       The virus doesn’t discriminate: A dead crow was even found on the White House lawn.
       West Nile can cause a potentially fatal brain inflammation. Anyone suffering such symptoms as a high fever, severe headache, confusion or difficulty thinking, stiff neck or severe muscle weakness should see a doctor right away. It has struck Americans as young as 16, but those most at risk are over 50.
       For every case of West Nile encephalitis, 150 more people are thought to be mildly infected — not sick enough to see a doctor.

They get a flu-like illness, with fever, headache and muscle pains, that lasts two or three days.
       How does West Nile spread? It infects numerous types of wild birds, from house sparrows to crows. Mosquitoes spread it among birds, and then to people. A spate of dead birds can be an early warning signal that the virus is circulating in a certain spot.
       Aside from people, the mammals most vulnerable are horses. There is a horse vaccine but not a human one, nor is there any anti-viral treatment — victims get supportive care.
       So preventing mosquito bites is important. Some health departments track bird deaths in deciding when to spray insecticides, but the CDC says consumers can do a lot on their own:
* Wear a mosquito repellent containing DEET; those without DEET aren’t nearly as effective. Follow the label’s instructions carefully, especially when applying to children.
* Stay indoors at dawn and dusk, when mosquitoes are most active.
* Get rid of mosquito breeding grounds on your property. Don’t allow water to stand for more than two days. Mosquito eggs need only a little water to hatch, and many species don’t fly long distances, so West Nile-bearing mosquitoes were probably born nearby. Typical culprits are empty paint cans collecting water under decks, unused pools, blocked rain gutters, flower pots and forgotten buckets.
* Those highly touted gadgets that catch bugs by mimicking the carbon dioxide people exhale aren’t proven to reduce the number of mosquito bites. They might attract a neighbor’s mosquitoes to your yard, or kill only one species instead of another type more likely to carry West Nile.
       “It’s a lot less expensive to rely on the old-fashioned methods,” Petersen says.

Sources: Chris Rooney, WNYT-Albany, N.Y.; CDC; New York City

Department of Health
The West Nile virus is a mosquito-borne flavivirus common in Africa, West Asia and the Middle East. It was first seen in the eastern United States in the summer of 1999.

       The Mosquito Control Association also recommends frequently changing birdbath water, stocking ponds with mosquito-eating minnows and using larvicides in unavoidable standing water.
       People can’t get West Nile from each other or by touching an infected animal. Zoos with exotic birds are not considered particularly risky — wild birds spread West Nile, and exotic birds that get it usually die quickly.
       But even as West Nile races across the country, there’s no real predicting how big a threat it will pose each year. Abroad, West Nile hides for years between periodic epidemics — a pattern likely here, too, says Petersen.

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