WCVM infectious disease specialist gives facts about equine herpes virus to Saskatchewan horse owners
APRIL 11, 2008 -- More than 300 members of Saskatchewan’s horse industry learned the facts about equine herpes virus from infectious disease specialist Dr. Hugh Townsend at an information seminar in Saskatoon last night.
Organized by the The Farm Animal Council of Saskatchewan Inc. and the Western College of Veterinary Medicine, the two-hour session focused on the neurologic form of equine herpes virus type 1 (EHV-1) that’s at the centre of a recent outbreak among Saskatoon-area horses. EHV-1 is a contagious virus that can be transmitted among horses through aerosol and through direct and indirect contact. EHV-1 can’t be transmitted to humans or to other animal species, and it is not a reportable disease in Canada.
OUTBREAK SIMILAR TO OTHERS
On March 14, WCVM's Large Animal Clinic suspended its equine clinical services after admitting two horses from a local riding stable that proved to be suffering from the neurologic form of EHV-1 infection.
During the next three weeks, veterinarians identified more affected animals at the same stable and at a second private farm. It’s believed that all cases on the second farm are linked to the initial outbreak of EHV-1 at the first farm.
As of April 11, WCVM veterinarians believe more than 100 horses at two farms in the Saskatoon area were exposed to the contagious virus. About 20 per cent of those horses developed clinical signs of the neurologic form of EHV-1, and one horse was euthanized due to severe neurologic signs.
As Townsend pointed out, the percentage of horses affected by the neurologic form in this recent outbreak is very similar to what has been seen in other outbreaks of EHV-1 throughout North America.
“EHV-1 is not a new disease: we’ve seen it for many years. Based on the numbers that we have for this outbreak, it does not seem that our situation is different or more severe than what has been seen in other situations,” said Townsend, a professor in WCVM's Department of Large Animal Clinical Sciences and a a senior research scientist at the Vaccine and Infectious Disease Organization (VIDO).
Townsend added that there’s no scientific evidence indicating that recovered horses increase the risk of EHV infection to other horses. “Extrapolating from studies conducted in the United States, it seems likely that about 10 per cent of the horses in Saskatchewan carry the neurotropic strain of EHV-1, and have probably done so for many years. Currently, there is no evidence to suggest that these horses should be treated or managed differently from any of their herdmates.”
With the voluntary isolation period drawing to a close on affected farms and no evidence of further spread of the disease, Townsend urged horse owners to adopt reasonable precautions when resuming normal activities and events. “I would argue that with today’s heightened awareness, the risk of spread of infectious disease among horses in Saskatchewan is less than it was prior to the outbreak.”
FOR MORE INFORMATION
Horse owners should contact their local veterinarian for further information about EHV-1, or if they suspect disease in their own horses. For general information about EHV-1, its clinical signs, treatment and control of the virus, please click here to download an EHV fact sheet or check the links below for additional resources.
• Information from the American Association of Equine Practitioners (AAEP) with additional input from Dr. Katharina Lohmann: Equine Herpes Virus Fact Sheet.
• Information from the Merck Veterinary Manual.
• "Infectious disease control: recommendations for biosecurity and vaccination". By Dr. Katharina Lohmann, Western College of Veterinary Medicine. Source: American Association of Equine Practitioners (AAEP).