- The pet horse Tardy, an 8-year-old gelding belonging
to a southwestern Minnesota farm family, began to lose coordination in
his hind legs Thursday. By the next day, he couldn't stand. And by Sunday
he was chewing and biting uncontrollably and squealing constantly.
The owner, in consultation with Dr. Lynn Buysse, a veterinarian at Minneota
Veterinary Clinic, decided to put him to sleep Sunday morning, just hours
before preliminary test results confirmed their suspicions: Tardy was infected
with the West Nile virus, Buysse said.
The horse is at least the fifth in Minnesota, including one in Roseau County
that was destroyed last week, suspected of carrying the mosquito-borne
virus. The state Department of Health first verified the presence of the
virus in Minnesota last week after testing two dead crows.
Buysse said many horse owners in southwestern Minnesota didn't take the
West Nile threat seriously, but since cases were reported last week, her
clinic has been flooded with calls for vaccinations.
Tardy lived on a farm near Boyd, about 20 miles north of Minneota. Buysse
declined to identify his owners.
"He was suffering badly," she said Sunday night. "It was
very painful for him."
And for the family, who went for a drive while Buysse injected the horse
to put him to sleep.
Buysse had submitted a blood sample to a diagnostic lab at South Dakota
State University in Brookings, and it came back positive Sunday. The sample
also was sent to the National Veterinary Services Lab in Ames, Iowa, for
confirmation.
The horse is also being tested for rabies, which causes symptoms similar
to those of West Nile. But Buysse said she was confident that the horse
had West Nile when she first examined it Thursday night. She had heard
that some dead crows in the nearby town of Dawson had been found a few
days earlier.
She said she had been preparing for the virus' arrival since April, when
she began administering vaccinations and educating owners about the need
to vaccinate against West Nile. "We always knew it would eventually
come here," she said.
North America's first case of West Nile was identified in New York in 1999.
It has spread west and south since, killing 18 people and more than 200
horses. It is particularly deadly to crows and horses, which, like humans,
can contract the virus when bitten by a carrier mosquito. About one-third
of the horses that contract it die.
No people in Minnesota are known to be infected. The virus is rare in humans
and does not usually cause serious illness in healthy people. There is
no vaccine for humans.
The four other horses at the family farm near Boyd were vaccinated Saturday.
They have not exhibited any signs of the virus, Buysse said. Infected animals
and people are not contagious. Tardy had not been vaccinated.
Buysse guessed that about half of the horses in southwestern Minnesota
have been vaccinated. She said drug supply is not an issue right now.
"We have been talking about it since April," she said. "But
it's just such a new thing to us here. And there's a lot of horses out
there that don't see veterinarians on a regular basis."
She added that some horse owners "didn't really believe it would come."
The first round of vaccines is not foolproof, she said. A first dose will
protect only about 30 percent of horses. They need to be given booster
shots three to six weeks later.
The incubation period of West Nile, which can cause the potentially deadly
brain disease encephalitis, is about one to two weeks. After that, horses
start exhibiting symptoms similar to those of sleeping sickness. They often
lose coordination, first in their hind legs, then in their front legs.
Besides the two horses that have died in Minnesota, the other three suspected
of having the virus are in Hennepin, Clay and Stearns counties. Test results
were expected this week.
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