Equine Herpesvirus Outbreak Leads to Cancellation of Equestrian Events in Nova Scotia

Dr. Trevor Lawson is an equine practitioner in Nova Scotia as well as the president of the Canadian Veterinary Medical Association. He said a very high percentage of horses are carriers of herpesvirus, but that doesn’t mean they’ll get sick. (Galen McRae/CBC)

A significant outbreak of equine herpesvirus-1 (EHV-1) in Nova Scotia has prompted the cancellation of numerous equestrian events across the province, according to local veterinarians and horse owners. The outbreak, which has been linked to the death of four horses, has raised concerns within the equine community about the spread and management of this potentially deadly virus.

Dr. Trevor Lawson, an equine practitioner and president of the Canadian Veterinary Medical Association, confirmed that the four deceased horses were all from the same barn in northern Nova Scotia. The first case was laboratory-confirmed on November 3, with the subsequent three cases being considered presumptive positives. In an interview at his Carrolls Corner home, Dr. Lawson stressed the seriousness of neurological diseases in horses, noting that “quite often it does not go well,” and that approximately half of the infected horses succumb to the disease.

A horse receives treatment at CEU Cardenal Herrera University’s teaching hospital during the 2021 EHV-1 outbreak in Valencia, Spain. | Courtesy Dr. Ana Velloso Álvarez

The virus, known for its high transmissibility, can spread through airborne particles when an infected horse coughs, or through direct contact such as nasal secretions. Indirect transmission via shared water buckets or grooming equipment is also possible, as well as human-mediated spread through contact with infected horses.

Symptoms of the neurological strain of EHV-1 include fever, nasal discharge, weakness, and coordination problems. Dr. Lawson also highlighted that while many horses are carriers of the herpesvirus, not all will exhibit illness. He likened the virus’s behavior in horses to the way humans who carry herpesvirus experience cold sores under stress, suggesting that stressors such as transportation could trigger outbreaks in equine populations.

Bruce Trenholm, who owns Creek View Farm in Northport, said he found out there was equine herpes in the province by chance from a vet he called for an entirely different reason. He thinks the virus should be reportable. (Kayla Hounsell/CBC)

The situation is considered critical, with the next two weeks being pivotal in determining whether the virus has been successfully contained. Despite the outbreak’s current restriction to a single barn, the exact location of which has not been disclosed, the uncertainty of its spread remains a concern.

Equine herpesvirus is not federally reportable in Canada, a fact that has sparked debate within the equestrian community. In Ontario, the virus is reportable, meaning veterinarians must notify the Ministry of Agriculture upon diagnosis. However, in Nova Scotia, such reporting is not mandated. Dr. Lawson believes this approach is appropriate, given Nova Scotia’s differing equine industry dynamics compared to Ontario’s racing-centric industry.

A horse suffering from neurological symptoms caused by EHV-1 is treated in Valencia, Spain.ANA VELLOSO/VETERINARY TEACHING HOSPITAL CARENDAL HERRERA

This lack of mandatory reporting has led to frustration among horse owners. Bruce Trenholm of Creek View Farm in Northport expressed his concerns about the lack of communication, having discovered the outbreak only through an incidental conversation with a veterinarian. Similarly, Nikki Porter from Rock’n Horse Ranch in Amherst emphasized the need for transparency and honesty within the equine community to effectively manage and prevent the spread of the virus.

Nikki Porter, who helps run Rock’n Horse Ranch in Amherst, N.S., cancelled a horse show and a clinic, which she said was the responsible thing to do, but estimated it cost her $5,000.

The financial impact of the outbreak is also being felt by horse owners and event organizers, with canceled events resulting in significant losses. However, as Trenholm and Porter pointed out, these financial sacrifices are necessary to prevent further loss of equine lives and to ensure the health and safety of the broader horse population.

As the situation evolves, the equine community in Nova Scotia remains on high alert, implementing stringent biosecurity measures and awaiting further developments. According to CBC News, the response to this outbreak will be crucial in shaping future policies and practices regarding equine herpesvirus management and reporting in the province.