Manitoba urges caution over horse herpes exposure

A group of out-of-province horses showing in southwestern Manitoba in recent weeks may have been exposed to a notorious equine virus before making the trip, provincial animal health officials warn.

Manitoba’s chief veterinary officer, Dr. Wayne Lees, on Wednesday posted a notice to Manitoba horse owners and veterinarians about three horses at an out-of-province horse facility showing signs consistent with equine herpesvirus myeloencephalopathy (EHM) starting Oct. 2. One of the horses was later confirmed as positive for equine herpes virus 1 (EHV1) and two of the animals have now died of their illness.

Although none of the horses from that group were reported to have been in Manitoba, other horses from the same out-of-province facility were at a horse show in Brandon “during the same time frame,” Lees wrote.

Furthermore, Lees wrote, a horse at a separate out-of-province facility — having had direct contact with the horses from the first facility that traveled to Brandon — has now begun exhibiting “respiratory signs consistent with EHV1.”

That case hasn’t yet been confirmed as equine herpes, Lees said.

No affected horses have been reported in Manitoba to date, Lees said, but his office plans to “work closely with Manitoba veterinarians to monitor the situation.”

EHV1 is a common and contagious virus in horse populations, leading to respiratory disease, abortion outbreaks and, in rare cases, EHM, a neurological disease.

Reported cases of EVH1, especially involving EHM, have been on the rise across North America in recent years, Lees’ office said. There have been several outbreaks of EHM linked to horse shows and large equine facilities.

A new strain of the virus, neurotropic equine herpes 1 (nEHV1), has been associated with this emerging disease, Lees wrote. The latest outbreak in Western Canada occurred in May and June, linked to horses that attended or were in contact with other animals that attended a national cutting horse competition in Utah.

No new cases from that outbreak have been identified since early June, Lees wrote.

Basic biosecurity precautions for horse owners against equine herpesvirus include:

• not sharing equipment, tack, feed buckets, water buckets or trailers;
• limiting direct contact between horses from different locations attending shows or events;
• washing or disinfecting hands in between handling individual horses, if handling several;
• using clean footwear and clothing when moving between horse farms or between groups of horses;
• vaccinating horses against EHV1 and other common infectious diseases (there are no vaccines for nEHV1);
• monitoring horses for signs of fever, loss of appetite, nasal discharge, depression or weakness, especially during a 14-day window upon returning from shows;
• isolating sick horses from other horses, allowing no direct contact; and
• cleaning and disinfecting all equipment and environment exposed to sick horses. Disinfectants such as bleach are not effective unless a thorough cleaning has taken place first, Lees wrote.