A horse at Fairfield Equine Associates in Newtown, Conn., that tested positive for the neurologic form of equine herpesvirus-1 (EHV-1) last week does not appear to be linked to the group of imported horses whose distribution gave rise to an outbreak in Florida and one death in California.

According to Rick Mitchell, DVM, the horse had arthroscopic surgery for lameness at the practice on Dec. 19. The animal developed a moderate fever on Dec. 24 that was treated with analgesics. The horse’s temperature was considerably higher the next morning, prompting veterinarians to submit samples for EHV-1 testing.

“It has not now had a fever since last Thursday (Dec. 28) morning, and it has never shown neurologic signs, but it did swab positive for the neurologic form,” Mitchell said. “The only positive aspect of it, relative to the neurologic form, is the swab suggests it is the same virus, but otherwise we’ve seen no symptoms.”

The horse has been isolated at the clinic since the test results confirmed EHV-1 last week. Mitchell said one surgeon at the clinic has been caring for the horse and taking full biosecurity precautions. Five other horses were in the clinic with the affected horse before test results were obtained. These horses also are being held in a voluntary quarantine separate from the test-positive horse.

“The other five horses that were in the clinic all seem to be normal,” Mitchell said. “We are maintaining them there in a self-imposed quarantine. The state has not imposed a quarantine, the feds have not imposed a quarantine on us.”

According to Mitchell, the timing of the horse’s fever (Christmas Eve) could not have been better, as the hospital was closed, thereby minimizing traffic.

A public release available on the Fairfield Equine Associates Web site (www.FairfieldEquine.com) states the hospital is not admitting horses to the facility as outpatients or inpatients. The Fairfield staff has made alternative arrangements with a local hospital for any emergency hospital or surgical care that might become necessary.

“No horses have come or gone from the clinic since we were notified that the horse did indeed have the bug,” Mitchell said.

Veterinarians have not been able to establish a link between this horse and any of the horses connected to the Newburgh import group that sparked the Wellington outbreak. According to Mitchell, the horse currently isolated at Fairfield lives alone on a farm in Vermont and has not been in contact with other horses other than those at the hospital. Mitchell stated he believes this case to be an example of EHV-1 latency.

“Several of us practitioners of a certain vintage are of the opinion that this virus is present in the horse population, and that we know that horses are affected and are latent carriers,” Mitchell said. “Horses that used to get fevers of unknown origin left and right, when subjected to stress, are now being tested for EHV-1. I genuinely believe that this virus has been here all along.

“I’ve had horses on the show circuit, a horse in Palm Beach, that in past years developed (EHV-1) and it didn’t turn into a pandemic,” Mitchell said. “If people were responsible and careful about how they handled those horses, subsequently it just petered out after a while.”

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