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BUSH RACING POSES AN EQUINE DISEASE RISK – AND NOT JUST FOR THE PARTICIPANTS
by Natalie Voss, Paulick Report
If you’re a subscriber to the Equine Disease Communication Center, you’ve seen a
fair number of alerts go out in recent years for new cases of Equine Infectious Anemia (EIA) and piroplasmosis. What you may not know is that the vast majority of cases of both diseases in recent years are coming from unsanctioned bush tracks.
In 2021, the U.S. Department of Agriculture recorded 103 cases of EIA, 84 of which
came from current or former racing Quarter Horses that had spent time on the bush racing circuit or been exposed to a horse who had.
The same year, 31 of 36 piroplasmosis cases came from racing Quarter Horses in the same circumstances. Since 2008, the agency has found 541 cases of piroplasmosis and 409 cases of EIA, all of which are racing Quarter Horses, many of which spent time on the bush circuit.
EIA is an incurable viral disease that can often be present without severe outward symptoms. An infected horse may, during acute infection, demonstrate jaundice, elevated heart rate or breathing, limb swelling, or bleeding from the nose. After an acute infection that have presented no outward signs, a horse becomes a
life-long carrier. The disease is spread by blood, which means a carrier has the potential to infect other horses nearby if a fly were to bite the carrier and then an uninfected horse. Federal animal health guidelines state that infected horses must either be isolated from others for the rest of their lives or euthanized.
Piroplasmosis is not endemic to the
United States. It’s also a blood-borne disease that can be passed between horses via several species of tick. Like EIA, its symptoms can be non-specific and may include fever, anemia, jaundice, weight loss, and labored breathing and can also include colic or death. Horses that are found to be positive for piroplasmosis must also be placed under quarantine until they test negative or be euthanized. They
may be treated with a drug called imidocarb dipropionate, but it can take a year or more after successful treatment for the horse to
test completely negative and be eligible
for quarantine release. The first cases of piroplasmosis began popping up in the United States in 2008 – making it, in epidemiological terms, a relatively new problem here – and came from the bush track population.
Dr. Angela Pelzel-McCluskey is an
equine epidemiologist for USDA/APHIS
and is responsible for doing epidemiological investigations on reportable equine diseases, including EIA and piroplasmosis. As a result, she has spent years studying the bush track scene.
The EIA and piroplasmosis cases she sees from the bush tracks are iatrogenic, meaning they originate from medical treatments on that population.
At one time, Pelzel-McCluskey said, the primary method of disease transmission in this population was the sharing of needles down the shed row. The USDA’s efforts to educate horsemen about the importance of using a different needle and syringe for each horse have made progress,
but there are still other vulnerabilities she said they’re not thinking about. Pelzel-McCluskey said that because there are no medication regulations
in unsanctioned racing, her research shows most horses on that circuit are getting some kind of injection at least once a day (including immediately prior to loading into the gate for a race).
“They’re already getting more injections than any other horse in America,” she said. “And they’ll reuse needles, syringes, and IV sets.
164 SPEEDHORSE March 2023