West Nile virus in four Minnesota horses

The Minnesota Board of Animal Health has announced that West Nile virus has been confirmed in four Minnesota horses through testing conducted by the U.S. Department of Agriculture’s National Veterinary Services Laboratories (NVSL) in Ames, IA.

The West Nile infections—Minnesota’s first confirmed cases in horses involve single horses in Hennepin, Clay, Roseau and Beltrami counties. The Board has confirmed that at least one of the horses died. Earlier, the Minnesota Department of Health (MDH) found the virus in dead birds from Hennepin and Mille Lacs counties.

Three of the four infected horses had previously tested positive in preliminary screening tests. The fourth had not been tested. In addition to the four confirmed West Nile infections, veterinarians have reported 10 other Minnesota horses suspected of having the virus. Blood or tissue samples from each of those animals will be analyzed at NVSL to determine if the West Nile virus is the culprit.

The Board of Animal Health and the Department of Health work together to watch for the virus in Minnesota. State law requires veterinarians to report any cases of West Nile virus or other equine encephalitis to the Board. The Board also has taken steps to educate Minnesota veterinarians and horse owners about the virus and what they can do to protect their animals from it.

Assistant State Veterinarian Paul Anderson was disappointed but not surprised to hear West Nile was found in Minnesota horses.

“With reports of West Nile in nearly every state around us, it was inevitable that we’d eventually see cases here,” Anderson said. “If any horse owners out there have not already vaccinated their horses for West Nile virus, they should definitely talk with a veterinarian about doing so.”