Doctors urge calm response to West Nile scare

Published 5:00 am Monday, August 5, 2002

Doctors and veterinarians are urging Mississippi residents toremain calm as the West Nile virus sweeps through the state.

Even in areas where the virus is circulating, very fewmosquitoes are infected with the virus, said Dr. Ryan Case of theAnimal Medical Center. Even if the mosquito were infected, lessthan 1 percent of people who get bitten and become infected willbecome severely ill.

Among those with severe illness due to West Nile virus, thechance of a fatality ranges from 3 percent to 15 percent and arehighest among the elderly, according to the Center for DiseaseControl.

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“In most cases, if you’re a healthy human you might feel likeyou have a flu, but that’s it,” Case said.

In addition, the CDC said chances of becoming severely ill froma single mosquito bite are very small.

Case said prevention steps to reduce the mosquito population areneeded, but people shouldn’t get too excited about the emergence ofthe virus here.

“It’s kind of become like a panic situation here and thereshouldn’t be a panic,” he said.

Although West Nile is new to Mississippi, with the first humancase diagnosed this year, it is no different than being wary ofEastern and Western Equine Encephalitis (EEE and WEE), he said.

Mississippi has vaccinated horses for EEE and WEE for more than35 years, he said, and begun vaccinating for West Nile nearly twoyears ago.

Although Case said people with unvaccinated horses shouldconsider vaccinating them, the vaccination process is a long one. Asecond vaccination is required three weeks after the initial shotand the vaccination does not fully protect the horse until threeweeks after the second shot.

“You’re looking at a good six weeks before you see any benefit,”he said.

Because of that, he said, all encephalitis vaccinations,including West Nile, should be conducted in the spring before itbecomes hot and mosquitoes are active.

West Nile is transmitted by mosquitoes through birds, accordingto the Centers for Disease Control, which lists 111 species ofbirds reported as susceptible to the virus. Many of those birds arenot native to Mississippi, where the virus has been most commonlyfound in blue jays and crows.

Case said he believes the virus is most frequently found here inthose two species because they are so prevalent.

“I think some birds are more susceptible because there are moreof them around,” he said. “I don’t think there’s anything in thebiology of the bird. I think it’s in the nature and frequency ofthe bird.”

There have been no confirmed cases of West Nile in LincolnCounty, Case said, and as of Thursday morning there was only onecase pending.

The closest confirmed case was a horse near McComb, he said.

Case said the higher infectious rate between West Nile and EEEprobably results from a lack of immunity to West Nile.

Equine encephalitis has been around a long time and one or twohuman cases are reported each year, usually in children, but WestNile is new to the landscape and therefore no immunities exist,Case said. There have been five confirmed human cases of West Nilein Mississippi this year.

West Nile, however, does not have the high mortality rate of EEEin horses. While West Nile will kill about 20 percent of infectedhorses, EEE’s mortality rate is nearly 100 percent.

Case said he expects incident rates of West Nile to declinerapidly in coming years as animal and human populace begin toestablish immunities.