Horse in S.D. tests positive for EHV-1 |

Horse in S.D. tests positive for EHV-1

A horse in Brown County, S.D., which is in north-central South Dakota, has been diagnosed with the wild strain of equine herpesvirus (EHV-1), said Dr. Dustin Oedekoven, South Dakota state veterinarian. The horse had recently traveled from Minnesota to a boarding facility in Brown County. The horse does not normally travel to competitions and events, but horses that are boarded near it do, said Oedekoven. “My staff is working with the veterinarian there, the facility owner and the horse owner to make sure appropriate steps are taken to limit the spread of the virus,” he said.

EHV-1 can manifest with respiratory symptoms, such as a cough and nasal discharge, or neurologic symptoms, such as lack of coordination, inability to stand, urine dribbling and loss of tail tone. Respiratory symptoms are much more common and treatable. Neurologic symptoms can be treated, but occasionally the most humane choice is euthanasia, Oedekoven said. EHV-1 can also cause abortion in broodmares. The horse in Brown County is exhibiting neurologic symptoms.

Some horses that have the virus pass it on before exhibiting any symptoms, and some horses can pass the virus on without ever exhibiting symptoms, Oedekoven said. A vaccine is available that helps prevent the respiratory symptoms and abortion, as well as reducing the likelihood of passing the virus on, but is ineffective against the neurologic symptoms.

“The virus is very common among the horse population, but often doesn’t cause disease until the horse has been under the stress of transportation, competition or just being around other horses,” Oedekoven said. The stress suppresses the immune system, so the virus can take hold.

The virus is spread by direct or indirect contact with nasal secretions, so any tack, equipment, facility or person who has come into contact with an infected horse can pass the virus on. Oedekoven recommends never sharing buckets, brushes or tack, and regularly cleaning and disinfecting trailers and anything else that may serve to harbor the virus.

Oedekoven said the cases that have been reported in surrounding states have centered mostly around barrel races, so that segment of the equine population is being extra careful. However, he said all horse owners should be aware of the situation and talk to their veterinarian about appropriate vaccinations for their horses. Even horses at brandings and community events have the potential to be exposed to the virus.

In addition to vaccination, Oedekoven recommends isolating horses that have been comingled with other horses for 28 days before allowing them to be around horses that remained at home. “Otherwise you may be exposing the horses back home to the same diseases that the horse that traveled was exposed to,” he said.

Check out the upcming Saturday, May 10 issue of Tri-State Livestok News for a more in-depth look at EHV-1.