Managing Equine Infectious Diseases at Canadian Racetracks

Woodbine’s Thoroughbred racing season had been already delayed by two months due to COVID-19 when more bad news came around the turn.

On May 16, the province’s regulatory body for horse racing, the Alcohol and Gaming Commission of Ontario (AGCO), confirmed two two-year-old Thoroughbred horses stabled in Barn 12 had tested positive for the neurotropic strain of the highly contagious equine herpesvirus, or EHV-1. One horse was euthanized at the Ontario Veterinary College.

“It felt like, oh my gosh, let’s just add an infectious disease on top of another infectious disease,” says Jessica Buckley, Woodbine Entertainment’s senior vice-president, Standardbred and Thoroughbred Racing, “It was a really difficult year for this to happen.”

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Mainly spread between horses by direct nose-to-nose contact, EHV-1 can also be transmitted indirectly via humans or contaminated objects. It causes respiratory illness (rhinopneumonitis, aka rhino), abortions and, rarely, neurological disease, which is also called equine herpesvirus myeloencephalopathy, or EHM. While both neurotropic and non-neurotropic forms of EHV-1 can lead to brain and spinal cord damage, it’s believed the former is more likely to do so.

A racetrack is a promised land for infectious diseases: the constant movement on and off property, comingling of horses and humans, varying adherence to biosecurity measures and a host of environmental factors that can affect equine immunity.

Disease outbreaks create havoc and send ripples industry-wide. Thankfully, compared to the United States where outbreaks of communicable diseases such as influenza, strangles, the deadly equine infectious anemia, and EHV-1 arise quite regularly, Canadian racetracks, although far fewer in number and overall horse populations, have comparatively emerged relatively unscathed. So far, that is.

“In the end,” says Buckley of this spring’s EHV-1 episode, “we had 41 horses test positive out of 1,830 horses on the backstretch at the time. It was contained 95 per cent to one barn. It took us six and a half weeks to clear all horses, which was very fast compared to other racetracks.”

It was Woodbine’s first outbreak since 2013, when five horses tested positive for neurotropic EHV-1 and one had to be euthanized.

Winnipeg’s Assiniboia Downs also battled the virus in 2014.

“It was a horse that wintered at a show horse barn. Those horses don’t get vaccinated until they start going around to shows. This horse came in shedding the virus and came down with the neurotropic form. That’s the scary one,” says Thoroughbred breeder and retired veterinarian Dr. Ross McKague. He’s also a founder and current director of the Manitoba Jockey Club (MJC), the group that owns and operates Assiniboia Downs.

That horse did die and three more that had been in proximity to it tested positive but didn’t show clinical signs, says McKague. The animals had been vaccinated, and “probably had enough immunity to kick it fast enough.”

Buckley notes, despite what many people suspected, all the infected horses at Woodbine had been vaccinated for EHV-1 prior to testing positive for the virus. While the vaccine doesn’t offer full-stop protection, it can lessen the disease’s severity.

The tricky part is that the virus can be latent in the body, meaning the horse can be a carrier with no external symptoms. And, unfortunately, the neurotropic form is resistant to prevention through vaccination. Stress plays a significant role in the disease’s emergence, especially when it comes to the neurotropic form in younger horses. Plus, says Buckley, experts believed this was a “very hot” or especially contagious strain.

Woodbine’s Mitigation Response

No matter how a disease lands at a racetrack, the response to its presence is critical.

The AGCO and Woodbine management immediately consulted with equine infectious disease experts from the Ontario Veterinary College, the Ontario Ministry of Food and Agriculture, as well as track veterinarians and the province’s Horseman’s Benevolent and Protective Association (HBPA). The plan, partly based on biosecurity protocols Woodbine established following 2013’s outbreak, was implemented May 17.

No horses could leave Woodbine without AGCO approval.
No horses were allowed in or out of the affected barn, including for training, except for emergency veterinary treatment or to be isolated.
Access to the affected barn was limited to essential staff. Horses were not allowed to leave except for emergency veterinary treatment or to be isolated.
All horses were temperature checked twice daily with results recorded on the stall door for inspection. Trainers were to contact their veterinarian immediately if they noted symptoms consistent with EHV-1 infection.
Equine dentistry was not permitted.
Only ponies housed in the same barn as a racehorse could be used to pony.

Buckley is confident the rigorous plans and procedures, especially daily testing, helped mitigate the virus’s spread. She also says it was advantageous that many COVID-19 biosecurity measures were already in place and atop everyone’s mind. These included a reduction of services, restricted personnel access and screening, limited travelling between barns, use of hand sanitizer and footbaths, and increased commitment to barn and equipment disinfection.

This year’s stall allocation was fortuitous, too, as it meant some barns sat empty. Horses that tested positive or showed symptoms such as fever were quarantined right away in these dedicated barns, completely isolated from the rest of the equine population.

Buckley commends the Woodbine community for adhering to protocols and doing their part to control the outbreak, notably when such measures proved labour intensive, inconvenient at times and often costly. Sue Leslie, president of Ontario HBPA calls the trainers frontline workers who were, “key in cooperating with their private vets to let us know if a horse wasn’t acting normally or had a temperature.”

Owners, on the hook for continual testing and other veterinary fees when they were already reeling financially from COVID, found veterinary bills quickly adding up. To offer assistance, the HBPA, spearheaded a one-time relief fund to cover some costs of the widespread EHV-1 testing. Several industry organizations contributed, says Leslie. (Looking ahead, Buckley says Woodbine is considering charging an annual $25 per horse stabling fee beginning in 2021 to offset some of the costs of future infectious disease outbreaks should they occur.)

For its part, Woodbine did an “exceptionally good job” of quarantining horses, credits Leslie. She was impressed with how stakeholders came together to work to contain the virus. Several meetings were held every week, “usually at night because that’s when the test results would come back,” she says. “We’d all convene on a conference call and discuss how we should proceed depending on the results.”

Better Policing

Racing regulators and tracks require certain vaccinations and/or veterinary inspection certificates for horses entering their respective grounds – usually a negative Coggins test for equine infectious anemia (a federally reportable disease under the Health of Animals act), both influenza and EHV-1 (rhino) vaccines and sometimes strangles.

For example, the stall application form for Hastings Park in Vancouver stipulates horses aren’t allowed on the grounds without current certification signed by a veterinarian of current (January 20, 2020) flu and rhino vaccinations, proof of strangles vaccination within the last three years and a valid Coggins.

Requirements do vary on when those inoculations and tests need to have been done prior to arrival and can depend on where the horse is coming from (i.e. areas in the U.S. where certain diseases are more prevalent). To illustrate, Woodbine recently ordered that all out-of-province horses entering the property must be accompanied by a veterinary inspection letter. The horses listed must not have come from a barn where confirmed or suspected EHV-1, strangles or other disease in the last 30 days or had a fever. The certificate must include the horse’s latest temperature recorded by the signing veterinarian and the date of the EHV-1 vaccine including the name of the product administered. According to Woodbine’s Thoroughbred Rule Book, for any other horses entering the stable area, a Coggins test and flu/rhino vaccination record valid within the year must be presented to the stall office within seven days of arrival.

Manitoba’s McKague says enforcing at-the-gate requirements is key to keeping diseases at bay.

“Having it on paper and actually making sure it’s adhered to is another thing. The problem is racetracks are so desperate for horses, they don’t want to turn anybody away.” He cites his own example from a few years ago when he sent two horses to Woodbine for training.

“After a few weeks I got a call from the office saying they didn’t have a vaccination record or a Coggins. Well, the veterinarian had forgotten to send it in. They weren’t checking that at the gate, let’s put it that way,” he says, admitting he understands where things could go awry.

“It’s pretty tough when a load of horses comes in and you say, ‘No. You’re going to have to go to a farm and be tested for a while because you’ve got a horse with a snotty nose.’”

When his own Assiniboia Downs was hit with EHV-1 six years ago, “We didn’t have any designated protocols. Nobody did,” admits McKague. At the time, the Manitoba Horse Racing Commission instituted strict quarantine requirements through the MJC that were primarily pulled from those established by the American Association of Equine Practitioners.

In the years since, there’s been increased awareness and education around biosecurity and how it can keep horses and humans healthy, and therefore productive. McKague himself was part of a team of industry stakeholders tasked to develop equine biosecurity on-farm protocols called the National Farm and Facility Level Biosecurity Standard for the Equine Sector.

Released in June 2016, the voluntary set of guidelines and recommendations are designed to help horse owners and custodians in protecting horses from contagious diseases. A year later a companion document, National Farm and Facility Level Biosecurity User Guide for the Equine Sector, was released.

Similar precautions are in place in the US; for example, at Gulfstream Park, as per the Florida Department of State’s Pari-Mutuel Wagering Rules, the following must be on file for each horse at the racing office no later than the animal’s arrival date:

a registration certificate;
negative Coggins test that expires no earlier than January 1, 2021;
a certificate of veterinary inspection, dated within 72 hours of arrival by a licensed veterinarian, stating the horse has been vaccinated for EHV-1 and equine influenza within a minimum of 14 days and a maximum of 90 days prior to entry and has not originated from a stable where EHV-1 was present or been diagnosed with the disease.

Equine Guelph also developed a program geared toward the Ontario racing industry on the topic. Called “Spread the Word, Not the Germs” the campaign used a peer-to-peer educational approach. Officials and personnel from the Ontario Racing Commission (ACOG’s predecessor) instructed racehorse caregivers at racetracks and training centres on infection control practices. You can find many of the materials here.

And finally, the HBPA of Ontario also provides this helpful guide outlining biosecurity measures to prevent EHV-1.