As West Nile Virus Spreads, Louisiana Struggles With Deadly Outbreak
13 cases reported in Texas and Mississippi in wake of 4 Louisiana fatalities
SUNDAY, Aug. 4, 2002 (HealthDayNews) -- The West Nile virus, which has killed four Louisiana residents in the last week, is breaking out all over.
After Gov. Mike Forest declared a state of emergency Friday, Louisiana health officials confirmed that the virus has infected a total of 58 people, including the four who succumbed to the disease.
Now, eight people in Texas and five in Mississippi have come down with West Nile encephalitis, a potentially fatal swelling of the brain which is the most serious effect of the virus.
The virus has also been found in birds and other animals in Oklahoma, Nebraska and the Dakotas. A dead crow carrying the virus was even found on the White House Lawn.
"I think it's no surprise that West Nile virus is going to become endemic across the country," says Dr. Susan McLellan, who does work for the infectious diseases sections at Tulane University School of Medicine and at Tulane's School of Public Health and Tropical Medicine, both in New Orleans.
Indeed, ever since the virus made its first U.S. appearance in the New York City region in 1999, health officials have predicted its spread.
"There's really nothing that would limit the ability of the virus to move southward," Dr. Stephen Ostroff, acting director of the U.S. Centers for Disease Control and Prevention's National Center for Infectious Diseases, said June 12 at a news conference to address concerns that the virus had moved into Florida.
Will it eventually cover the whole country?
"That'd be my bet," says John Roehrig, chief of the arbovirus diseases branch of the CDC in Fort Collins, Colorado. "I don't know when it will get to California, but eventually it probably will."
The virus is spread by mosquitoes that pick it up when feeding on infected birds and animals. Only about one-in-200 humans infected with the virus actually becomes seriously ill, McLellan says. Maybe 20-in-200 will experience less severe, flu-like symptoms.
Individuals over the age of 50 and those with compromised immune systems are the most vulnerable to serious illness. The four victims this year in Louisiana were all over the age of 50. In 1999 in New York City, 55 people were hospitalized and seven died, most of them elderly.
Since 1999, the virus has made it to more than 30 states. Last year there were a total of 66 cases, and this year there have been about 88 so far, but in a much broader area, Roehrig says.
The pattern of the virus's spread has also been no surprise. "It's going to be a matter of where humans are in regard to where the mosquitoes are," McLellan explains. "There may be areas with infected mosquitoes, but the people don't go there." Louisiana, with its swamps, marshes and lowlands, has a long history of humans co-existing -- not always harmoniously -- with mosquitoes.
"This is their environment," says Dawn Wesson, an associate professor at Tulane's School of Public Health and Tropical Medicine. "We have a history of mosquito-transmitted diseases around here and every year we see several of these diseases in addition to West Nile, but West Nile has been overwhelming."
The virus's appearance in other states may be less dramatic. "How fast the virus goes through the Great Plains states is anybody's guess," Roehrig says. "There's a lot of area between Omaha and Denver and not a lot of forest; plus there's a drought right now, which is not good for mosquitoes." Different regions of the country also have different species of mosquitoes, which will affect how rapidly the virus spreads and how rapidly the public health system can respond.
The only defense now is a good offense: eliminating places where mosquitoes might breed (usually in sitting water), killing the mosquitoes themselves and covering yourself with insect repellant so you won't get bitten.
Experts are optimistic that the beast can be beat. "We had yellow fever here up until the end of the 19th century, and it was eradicated basically by getting rid of breeding grounds near where people live," McLellan says. "It was eradicated from this state long before pesticides."
Louisiana lawmakers, meanwhile, are pushing for increased federal aid to combat the outbreak.
Republican state Sen. Tom Schedler said a special legislative fund of $6 million to $7 million could be depleted shortly as health officials continue spraying programs to kill infected mosquitoes.
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