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West Nile may not have killed horse

As tests place the cause of a Pasco animal's death in doubt, a Hernando County horse is tested for the mosquito-borne virus.

By MATTHEW WAITE

© St. Petersburg Times, published August 15, 2001


As tests place the cause of a Pasco animal's death in doubt, a Hernando County horse is tested for the mosquito-borne virus.

Vanity, the 30-year-old northeast Pasco County horse whose suspicious death last week triggered concern about the West Nile virus, might not have died from the mosquito-borne illness after all.

Preliminary test results from a federal lab in Iowa came up negative for West Nile and eastern equine encephalitis, a more common strain of encephalitis, researchers at the Florida Department of Agriculture said Tuesday.

With the possible elimination of a case of West Nile in Pasco County came the news that a horse in Hernando County is also being tested for West Nile. However, state epidemiologist Steven Wiersma has said it is not unusual for horses to be tested if they have symptoms of a mosquito-borne illness.

Another test still must be completed to be sure that Vanity didn't have the virus, said Dr. Bill Jeter, diagnostic veterinarian manager of the state bureau of animal disease control. But he said preliminary test results were "encouraging."

"Just because we have a negative on the first test doesn't kick out" the possibility that the horse had West Nile or eastern equine encephalitis, Jeter said. Final test results were expected later this week.

However, researchers think that if the horse did have West Nile, it didn't have it for long. A shorter infection time means this first test is more likely to have accurate results.

As for encephalitis, the Department of Agriculture's Dr. Ashby Green said Vanity was vaccinated and still had some of the vaccine in her system, which should have prevented the disease.

So far, two north Florida residents have been diagnosed with West Nile virus since the disease was first found in Florida last month. Both were from Madison County. Nobody in Florida has died from West Nile.

Currently, 29 north Florida counties are under a medical alert to be aware that West Nile could be in the area.

In humans, West Nile can sometimes cause encephalitis, a swelling of the brain, which can come on quickly. Symptoms include headache, fever, fatigue, dizziness, sensitivity to light and confusion.

In horses, the symptoms of eastern equine encephalitis and West Nile are stumbling, staggering, a wobbly gait more often affecting the back legs, weakness and a hard time lying down and getting up.

When Vanity was put down, she exhibited telltale signs of West Nile virus, including a wobbly gait and partial blindness, said Brooksville veterinarian Doug Davenport, who examined the animal.

- Staff writer Tamara Lush contributed to this report.

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