Todd County horse tests positive for West Nile virus

Publish Date
Author
Dan Callahan

St. Paul, MN: An unvaccinated 2-year-old Belgian colt in Todd County was reported positive for West Nile virus (WNV) August 30 and marks the first confirmed equine case in Minnesota this year.

The horse became unable to rise in the morning of August 26, and died that afternoon. The owner reported three horses on a neighboring farm all died with similar clinical signs a few days prior to the colt showing signs of illness. While the other horses were not confirmed with WNV, this highlights the importance of vaccination and testing for this disease because it can be spreading locally via mosquitoes. In addition to the Todd County horse, the Board also received a report of an alpaca in Scott County also tested positive for WNV at the end of August.  

“Taking action to vaccinate your animals is the best way to protect them from WNV,” said Dr. Heather Damico, senior veterinarian in charge of the Board’s equine program. “We often see reports of cases in horses that are either unvaccinated or under vaccinated, which means they didn’t receive their annual booster shot. Vaccines can prevent infection or reduce severity of disease if the horse gets sick. Please vaccinate horses according to your veterinarian’s recommendation.”

WNV is regularly found in the U.S. and birds serve as the primary host of the disease. The virus circulates between infected birds and mosquitoes. Once infected, the mosquitoes can transmit the virus to horses or people. Infected horses cannot spread the virus to people or other horses. The virus can cause inflammation of the brain and spinal cord. Infected horses may or may not show neurological symptoms and may recover completely, especially those who have a history of annual vaccination.

In addition to vaccinations horse owners can reduce environmental risks of WNV by reducing mosquitoes:

  • Change water in drinking troughs every week.
  • Mow long grass.
  • Drain stagnant water puddles.
  • Remove items mosquitoes use for breeding grounds, like old tires and tin cans.
  • Place and maintain screens over windows and stable doors.
  • Use mosquito repellents to protect horses and people from mosquito bites.

This is a high-risk time of year for WNV transmission. The Metropolitan Mosquito Control District has already reported WNV in routine mosquito samples in the metro area. The Minnesota Department of Health (MDH) has reported multiple human cases. Non-negative test results for West Nile virus disease must be reported to the Board of Animal Health.

For more information on WNV, visit our website.

Mosquitoes can transmit West Nile virus to people; potentially leading to serious illness. Information about the disease in people can be found at the MDH website.