Augusta County farm quarantined after horse contracts EHM

AUGUSTA COUNTY, Va. (WHSV) – A horse in Augusta County has been euthanized after contracting Equine Herpesvirus Myeloencephalopathy (EHM), a mutation of Equine Herpes. The Virginia Department of Agriculture and Consumer Services has quarantined the farm where the horse was and seven other horses that were exposed.

“Equine Herpesvirus Myeloencephalopathy is actually from one of the herpes viruses known as Equine Herpes Virus One and Four. Those are the two main variants that can mutate over to EHM which is what everybody is most concerned about,” said Dr. Wynne DiGrassie, owner of Mountain View Equine Hospital in Steeles Tavern, VA.

Horses can survive less severe cases of EHM but it has a 30% mortality rate. Anti-inflammatory drugs are sometimes used to treat the disease but there is no cure.

“It’s always a big scare because this is potentially a fatal disease but it’s not as common as people think. The original herpes virus itself, most horses carry it and have it in their body,” said DiGrassie. “It’s just a matter of who actually mutates and who comes into contact with the mutated virus.”

While EHM is uncommon it is highly contagious.

“Equine herpes virus in general is just a virus like any other virus out there that’s usually a respiratory type virus that gets spread by nasal secretions, gets spread by nose to nose contact, sneezing. As well as humans spread it a lot,” said DiGrassie.

Dr. DiGrassie said that humans can spread the disease through contact with horses.

“Maybe we go to another barn, we haven’t washed our hands, haven’t washed off our boots, haven’t changed our clothes. We can spread it on ourselves that’s what they call fomites, it’s just other things like tack, equipment, brushes, wheelbarrows, all of that stuff is another way it can be spread from horse to horse,” she said.

The mutation that causes EHM makes it far more devastating than regular equine herpes.

“That herpes virus that normally just causes respiratory disease mutates inside the horse and then forms this neurologic form where the horse is kind of wobbly, which is what we call ataxia, can’t get up on its own, sometimes they’re dribbling urine, they sometimes go down and can’t get back up,” said DiGrassie.

Other clinical signs of EHM include a fever, nasal discharge, depression, and a loss of tail tone.

Dr. DiGrassie stressed the importance of keeping horses up to date on their herpes virus vaccine and taking additional steps to be mindful of the disease.

“Watch when you bring in new horses to the property. Make sure you quarantine them for at least two weeks because horses in times of stress that’s usually when this herpes virus is going to rear its ugly head. So make sure you quarantine horses for a period of time when they come back to a show or on to a new property,” she said.

VDACS said that the farm in Augusta County will be quarantined for 21 days and that the other seven horses will have their temperatures taken twice a day. It said so far they have not shown any signs of EHM.

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