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Springtime: Flowers, rain and West Nile worries

Springtime: Flowers, rain and West Nile worries

From Rea Blakey
CNN Medical Unit

RICHMOND, Virginia (CNN) -- At Level 3 public health labs in Virginia, technicians are testing dead birds for the mosquito-borne West Nile virus. Underscoring how seriously this virus is taken, only a Level 4 lab, where ebola or anthrax can be handled, has more safety features.

West Nile encephalitis is an infection of the brain. The virus has historically been found in Africa, western Asia and the Middle East. But in 1999, it was documented for the first time in the Western Hemisphere, according to the Centers for Disease Control and Prevention in Atlanta, Georgia.

Mosquitoes usually catch the virus from feeding on infected birds. Then, they pass it along to humans and other animals when they bite. Already this year in Virginia, at least two birds have tested positive for West Nile.

Map: Tracking West Nile  

"They're a lot earlier," says Virginia's Health Commissioner Dr. Robert Stroube, referring to the birds. "Last year that came in the summer. The year before they came in October."

"I think it's going to mean we're probably going to have a lot more birds -- and the more birds you have ... the more likely it is that humans can be infected," adds Stroube.

West Nile virus was detected in the United States in 1999. In 2000, it was on the move, reported in several states. By last year, it spread as far south as Florida, as far west as Iowa. Since 1999's first appearance through 2001, it has severely infected 149 people and killed 18.

This spring, steady rain throughout the Northeast and Midwest, on the heels of a mild winter, has created ideal breeding grounds for mosquitoes.

"The warmer the weather and the wetter the weather, the more favorable the environmental conditions are for having mosquitoes," says Stroube.

The solution is to head the problem off at the pass. "If you want to control mosquitoes, you have to hit them where they're breeding. You have to control the larvae," says public health entomologist David Gaines.

In Virginia, mosquito surveillance is already under way. Traps that attract the biting insects before and after they feast on people help officials track the trend.

Other areas are being sprayed with insecticide and places where water pools are being treated -- all in an attempt to contain the virus.

"The chances of trying to control it are virtually nil at this point in time. It's too widespread," Stroube says.

But not everyone is at high risk. "The people who are usually symptomatic are usually older, have other types of conditions which may make them more prone to getting infections," he said.

The CDC, however, has some reassuring news on its Web site. It says that even in areas where birds or mosquitoes with West Nile virus have been reported, very few bugs -- much less than 1 percent -- are infected. Add to that: Only 1 percent of people who are bitten by a virus-carrying mosquito get severely ill.


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