Deadly EHV horse virus detected again in King County stable

New case at Woodinville stable has Eastside equestrian community working together to ensure virus does not spread to other stables.

A Woodinville stable is once again under quarantine after another horse fell ill with a potentially deadly virus.

One case of equine herpes virus 1 (EHV) was reported on April 6 at Gold Creek Equestrian Facility — just a few miles outside of Bothell — where seven horses were euthanized last December due to the same disease. Most horses are infected with EHV as foals, which then lies dormant unless it is activated by stressors. When this happens, it becomes active, or neurotropic, and infects. Horses in this stage become highly contagious and can pass the virus in its active form to other horses.

“Be real careful right now in that neck of the woods, or even the whole state of Washington,” said Dr. Thomas Gilliom, a state field veterinarian.

The Eastside has a large equestrian community centered around Bridle Trails State Park, located between Bellevue, Redmond and Kirkland. Dana Kapela with Overlake Farms in Bellevue said in an email they are taking the relapse at Gold Creek seriously and are working with other farms in the area to ensure it does not spread to additional stables.

Gilliom said the infected horse at Gold Creek could have been exposed to the virus from a new source, but it is likely the horse had a latent form of the virus that became neurotropic.

“It’s just really hard to say,” he said. “We thought we were free and clear of it.”

As of the afternoon of April 9, all horses at the Woodinville facility were being monitored and their temperatures were taken twice daily. No other horses were thought to have the virus but a couple were showing slightly elevated temperatures, Gilliom said.

A horse’s normal body temperature is 100.5 degrees. Gilliom said horse owners should monitor for temperatures rising higher than one degree as well as keeping an eye out for other symptoms such as trouble breathing or walking and eye mucous.

“Everyone that has the ability to take the horse’s temperature twice a day, that’s what I would tell them,” he said.

While EHV does not infect humans it can be transmitted through contaminated clothing or riding gear. State Department of Agriculture spokesperson Hector Castro said riders should practice proper cleaning etiquette and disinfect gear.

“Certainly people can spread it if they’re not careful with how they’re using their equipment or gear,” Castro said.

Mortality rates for EHV infected horses can be as high as 30 percent while others survive to lead healthy lives. Of the 60 horses at Gold Creek last December, seven had to be put down as a result of the disease.

Treatment includes supportive care such as hooking the horse to IVs, draining the bladder since inability to urinate is a symptom and making sure the horses are fed and watered.

Gilliom recommended if people take their horses to shows or events that they keep the animals to themselves and avoid communal water or feed bowls. If they suspect their horse may be sick, they should call their veterinarian.

“Really watch your horse and again, take its temperature twice a day,” he said.

According to Animal Science, following an EHV outbreak, stables are generally quarantined for at least three weeks after the last case of the virus has subsided. All stable equipment should be cleaned or replaced and handlers should wash their hands and change their clothes after interacting with each horse. While the virus can survive for weeks on its own it is easily killed by common disinfectants.