Outbreaks of Equine Herpesvirus 1, or EHV-1, were recently detected in four of Utah’s neighboring states - Nevada, Idaho, Arizona and Wyoming. Although there aren’t any current outbreaks in Utah, the Utah Department of Agriculture and Food urges equestrians to be aware of the disease.
“Equine Herpesvirus 1 is a virus that ordinarily horses - by the time they’re two years old - have been infected with it and it’s in their bodies usually for life,” said Dr. Barry Pittman, state veterinarian at the Utah Department of Agriculture and Food.
“It’s an inapparent infection normally. Every once in a while, their immune system drops and it will manifest as a clinical disease. This EHV-1 can also mutate into a strain that’s more virulent. It’s called equine herpes myloencephalopathy - EHM. That particular disease, we get really concerned about because horses start showing neurological signs and will sometimes have to be euthanized because it gets severe,” he said.
There are currently no outbreaks of EHV-1 or EHM in Utah, but it’s important to be aware of the possibility. This time of year is typically when EHV-1 outbreaks spike.
“Nevada broke earlier this year, and we also had cases in Idaho, in Wyoming, in Arizona, so we are pretty much surrounded by the western states with sporadic outbreaks. The problem is the equine populations in all these states comingle together at certain events,” Pittman said.
If a horse has clinical signs of EHV-1 or EHM, it can readily spread its infection to other horses. Symptoms include fever, nose and eye discharge, lethargy and decreased coordination.
The virus can be spread by buckets, tack and nose-to-nose horse contact. Quarantine is effective, so horse owners should call ahead to event managers to check biosecurity measures at equestrian events. If an owner thinks their horse was exposed to a horse with an active infection, they should monitor their horse’s health.
“Since it’s in horses since the age of two, there is no magic time when this will go away,” Pittman said. “If they’re concerned, take their temperature a couple of times a day. A normal temp for a horse is 99 to 101° F. If there’s any elevation of a temperature or any signs of respiratory problems they need to notify their vet.”
