Utah Department of Agriculture and Food

Horse Racing Season and Equine Piroplasmosis

Jack Wilbur (801) 538-7098

      Cell (801) 243-2801

Dr. Barry Pittman (801) 538-7162


Horse Racing Season and Equine Piroplasmosis

In September of 2016, an outbreak of equine piroplasmosis in Utah and several surrounding states prompted the Utah Horse Racing Commission to initiate testing for this disease at sanctioned races on the recommendation of the Utah State Veterinarian. Since the increase in this disease continues across the United States, especially in racing Quarter Horses, nine states have required horses to be tested for this disease before allowing them to race.


During the past eight years there have been close to 400 positive cases of equine piroplasmosis in the United States, the vast majority in Quarter Horse racehorses. Since the majority of new cases and iatrogenic transmission of this disease in the country has been among Quarter Horse racehorses as a high-risk group, continued surveillance is important for early detection of new cases in Quarter Horse racehorses entering sanctioned racetracks. Testing at racetracks in additional states is needed for early detection of this disease. Early detection can prevent inadvertent spread within owner/trainer groups, dispersion of diseased horses in the racing industry, and expansion into other segments of the equine industry as these athletes are retired from racing.


Equine piroplasmosis is a disease of Equidae (horses, donkeys, mules, and zebras), and is caused by two parasitic organisms, Babesia equi and Babesia caballi. Although it is primarily transmitted to horses by ticks, the greatest risk for introduction of this this blood borne disease recently has been the spread mechanically from animal to animal by contaminated needles and where infected and non-infected animals are in contact, such as racing stables. Horses that are diagnosed with this disease are either euthanized, quarantined for life or, with federal approval, can undergo an experimental treatment that is closely monitored by state or federal veterinary regulatory personnel while in quarantine. If initially successful, this treatment may take horses over two years to be cleared by laboratory testing and the treatment regimen completed.