Manitoba horses may have been exposed to a potentially lethal equine virus during a horse show held at Brandon’s Keystone Centre earlier this month, warn provincial animal health officials.

Two animals have recently died from an outbreak of herpesvirus myeloencephalopathy (ETM) — otherwise known as “horse herpes” — in an out-of-province facility.

Several other horses from this same facility, though not the horses that died, were at a Manitoba Quarter Horse Association event during the Thanksgiving long weekend in Brandon.

“Neither one of these (two) horses travelled to Brandon,” Manitoba animal health surveillance veterinarian Dr. Glen Duizer told the Sun. “In that time frame in between, when the disease was more or less in that group of horses, there was at least some horses from that facility that went to the Brandon show.”

A third horse from a separate facility located in the same province, and which had direct contact with the horses from the first facility while in transport, has begun to show symptoms of the respiratory form of the disease. However, this third case has not been confirmed, and Duizer said the animal could have suffered from some other disease, such as a flu.

“This third horse was at the show with those horses, and was transported with those horses. It had the most exposure probably of any horse,” Duizer said. “It could have contracted it at the Brandon show or it could have contracted it while it was in the trailer travelling with the other horses. The likelihood is that it got it in the trailer, but we don’t know that.”

The names of the horse owners and in which province the disease originated are not being released by provincial officials.

Last Wednesday, notices were sent to all veterinarians and major equine associations within Manitoba by the province’s chief veterinary officer, Dr. Wayne Lees, warning of the potential exposure.

While Duizer said that veterinary officials in Manitoba are not aware of any cases of ETM in this province, it’s important to warn horse owners of the fact that their animals could have been exposed.

“It’s quite a significant disease if it does transfer. It’s also fairly contagious.”

It’s important that horse owners take steps to prevent exposure to these kinds of diseases, Duizer said. While horse herpes does not pose a risk to humans, those who handle horses should be careful they don’t inadvertently transmit the disease through contact.

Horse owners should remember to wash their hands in between handling different animals, packing and using personally owned feed and water buckets, and whenever possible, using a private trailer to move horses to shows instead of sharing with another owner.

The veterinarian also says horses should be vaccinated.

“If you keep your horse well protected with a good immunity … they become less susceptible to any disease, not just the disease they were vaccinated to.”

Duizer said he also spoke directly with the manager of the Keystone Centre to offer advice about how best to clean the stalls and the area where the horses were housed.

If horses show symptoms of any illness during a show, he recommends that the animal be taken out of the facility as quickly as possible.

“Take it somewhere close by until it’s fit to be transported.”

Republished from the Brandon Sun print edition October 25, 2011