A new case of equine herpes virus has been diagnosed at Washington State University’s College of Veterinary Medicine teaching hospital, even as the threat from a widespread outbreak appears to have lessened.
The horse involved was recently admitted to the hospital for an unrelated intestinal illness but was also suspected of having EHV-1.
Swabs confirmed the presence of the virus, the college reported on Wednesday. The horse had been placed in strict isolation at the time it was taken in.
That horse becomes the ninth case of equine herpes virus reported in Washington since the outbreak began in the Western United States last month. It is also the sixth case handled at WSU’s veterinary hospital. No horse deaths have been reported in Washington so far.
Two horses believed to have the virus have died in Idaho.
The outbreak took hold following a cutting horse competition in Ogden, Utah, at the end of April. Horses there came in contact with at least one other horse carrying a severe neurological strain of the virus.
The horses at the event then returned to their home ranches where they were in proximity to noninfected horses.
At least a dozen horses have died since the outbreak started among more than 400 horses at the event, the New York Times reported on Monday.
The two Idaho horses that died had been to the event, that state’s veterinarian reported. Of those, one was confirmed to have the neurological strain of EHV-1, and the other was believed to have had it based on symptoms, said Idaho state veterinarian Bill Barton.
The two dead horses belonged to different owners in Canyon County.
In all, eight cases have been reported in Idaho, including four of the neurological strain and four of a less severe respiratory strain, he said.
Authorities have said the threat of the outbreak is easing. “We’ve gone two weeks without any new cases being reported” in Idaho, Barton said.
The neurological strain of virus was first identified in 1971.
EHV only affects horses and animals of the camel family such as alpacas and llamas. It is harmless to humans. Horses that are infected often recover without serious complications, but must be quarantined to prevent spread of the disease.
The variability of outcomes may result from differences in horses’ immune systems and other health factors along with treatment, including fluids and anti-inflammatory drugs, Barton said.
In both Idaho and Washington, EHV-1 cases are reported to the state veterinarians.