West Nile Virus Spreads Fast, Prompting Fears

Federal health officials said Tuesday the West Nile virus had spread more quickly since resurfacing in the U.S. this summer, prompting fears of another record outbreak of the deadly mosquito-borne disease.

The virus, which killed 284 people and infected about 4,000 others in the United States and Canada in 2002, has been detected in mosquitoes, birds, horses and humans in 32 U.S. states in 2003, according to the U.S. Centers for Disease Control and Prevention. No cases have been reported in California.

Only about 20 states had reported similar activity at this time during last year’s outbreak, which was the worst since West Nile first surfaced in the Western Hemisphere in 1999.

“It’s too soon to predict the shape of the epidemic, but the signs all indicate that there is reason to anticipate a problem,” CDC Director Dr. Julie Gerberding said in a news conference.

The CDC said it had confirmed infections in three people in Texas and in another in South Carolina this summer.

Gerberding recommended that Americans take steps to drain mosquito-breeding areas in their yards and wear protective clothing and insect repellents when outside, especially in the hours between dusk and dawn.

Most people who are bitten by a West Nile-carrying mosquito suffer nothing more than headaches and flu-like symptoms, but the elderly, chronically ill and those with weak immune systems can develop fatal encephalitis and meningitis when infected.

U.S. health officials have been particularly concerned with the virus’ ability to spread through blood transfusions and organ transplants, giving the disease the potential to be far more common.

It is estimated that up to 200,000 Americans may have been exposed to West Nile since 1999, when it killed seven people in the New York City borough of Queens. An estimated 4.5 million Americans receive blood or blood products annually.

The U.S. Food and Drug Administration has spearheaded development of two tests designed to screen blood for the virus.

The FDA also has issued tougher guidelines on blood donation since last year’s outbreak.

In addition to new tools designed to ferret out the virus, U.S. researchers are working on a vaccine they hope would provide immunity to West Nile.