Pasco horse may have deadly virus

A veterinarian thinks the animal may have contracted West Nile disease.

By CARY DAVIS

© St. Petersburg Times,
published August 7, 2001

Preliminary tests on a Pasco horse showed that the animal likely has contracted the deadly West Nile disease. If confirmed, it would be the first case of West Nile in the Tampa Bay area and the southernmost case of the virus in Florida.

The horse, kept in the northeast Pasco community of Trilby, exhibited telltale signs of West Nile virus, including a wobbly gait and partial blindness, said Brooksville veterinarian Dr. Doug Davenport, who examined the animal.

A blood sample from the horse was tested at a state lab, where it revealed a "significant" chance that the animal has the deadly mosquito-borne virus, Davenport told the St. Petersburg Times Monday night.

That blood sample is on its way to the National Animal Disease Center in Ames, Iowa, to confirm the findings, he said.

"I would say there's a good possibility that it is positive," Davenport said. "Right now, it's just a suspect. It's not confirmed yet."

Davenport said he did not know when the results would be available.

Citing confidentiality obligations, Davenport would not identify the horse's owners or the where the animal was kept. He would only say it was an old horse and would not confirm whether it was alive or dead. State epidemiologist Steven Wiersma confirmed that the Trilby horse had been tested. He said it is not unusual for horses to be tested if they have symptoms of a mosquito-borne illness.

So far, two north Florida residents have been diagnosed with West Nile virus since the disease was first found in the Sunshine State last month. Both were from Madison County.

Madison and 27 other North Florida counties are under a medical alert issued by the state health department for West Nile and eastern equine encephalitis, a more common form of mosquito-borne encephalitis. Eastern equine encephalitis killed a 9-year-old Pensacola boy last month.

Nobody in Florida has died from West Nile.

A horse in Seminole County in central Florida recently tested positive for eastern equine encephalitis. So far, 15 horses have been found to have the West Nile virus in North Florida counties.

West Nile is a strain of encephalitis that causes an inflammation of the brain.

In humans, the onset of encephalitis can come quickly, with symptoms such as headache, fever, fatigue, dizziness, sensitivity to light and confusion.

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

The disease is spread by mosquitoes that pick up the virus from infected birds. It cannot be directly passed from horse to human.

The disease was more common in Africa and Europe before 1999, when nine New York City area residents died from the first outbreak in the United States.

Davenport, the veterinarian, said a vaccine for the disease was available for horses. The drug has been given conditional approval, he said, but has not yet been distributed to veterinarians.

There are no vaccines available for humans.

The Florida Department of Health maintains a toll-free West Nile virus hotline so people can find out the latest information on the disease. The 24-hour number is 1-888-880-5782.

-- Staff writers Matthew Waite and Tamara Lush contributed to this report.

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