CHARLES TOWN, W.Va. - Although it is not clear why, horses are particularly susceptible to the West Nile virus, a Jefferson County health official said.
An increasing number of horses in the country are showing up dead or showing symptoms of the disease, and in Minnesota, eight have died from the virus, said James Hecker, chairman of the Jefferson County Board of Health.
The risk is not great for horses at the Charles Town Races because horses that are highly valued are usually vaccinated for the disease, Hecker said.
Infected mosquitoes carry the West Nile virus and can spread it by biting a human, animal or bird.
In humans, symptoms of the virus are usually mild, but the most severe cases can be fatal, health officials say.
A dead crow that was found last week in Greenbrier State Park near Boonsboro tested positive for the virus, making it Washington County's first confirmed case of the disease.