MADISON, Wis. — A horse in Trempealeau County has tested positive for the mosquito-borne West Nile virus, the state Agriculture Department reported. The agency didn’t release the exact site in the 742-square mile Mississippi River county. The case is the first in Wisconsin this year. The disease causes brain inflammation. It is fatal in 30% to 40% of infected horses. Horses experience fever, losr incoordination and appetite, develop tremors, and cannot stand up. The American Association of Equine Practitioners recommends vaccinating all horses.

West Nile profile

In humans the symptoms are fever, headache and vomiting. One in 150 human cases are serious, some fatal. New outbreaks recede when the first frost kills the season’s mosquitos.