When a horse crosses an international border, the country the horse is traveling to requires proof that the horse won’t threaten the health of the resident equine population. The University of Kentucky Maxwell H. Gluck Equine Research Center is often sought for research-based information that will define appropriate procedures to safeguard horse health. This research is very important, because horses travel more than any other animal species (for competition, breeding, and change of ownership, among other reasons).

The movement of horses internationally is underscored with the upcoming Alltech FEI World Equestrian Games (WEG) Sept. 25-Oct.10 at the Kentucky Horse Park (KHP), when about 750 horses representing 62 countries will ship to the Bluegrass. This isn’t the first event for which many horses have been shipped to the United States; hundreds of horses shipped into Georgia for the 1996 Olympic Games. One of the most pressing issues, then and now, is equine piroplasmosis, a disease of Equidae (horses, donkeys, mules, and zebras) caused by two parasitic organisms, Theileria (Babesia) equi and B. caballi. The blood-borne disease is usually transmitted to horses by certain tick species, but it can also be spread via contaminated needles. But since the disease is transmitted only by exposure to infected blood, it’s easier to control than many other diseases.

Once a horse contracts piroplasmosis, clinical signs appear in seven to 22 days. Cases can be mild or severe, depending on the amount of the organism in the horse’s blood. An acute case can have fever, anemia, jaundiced mucous membranes, a swollen abdomen, and labored breathing. A roughened hair coat, constipation, and colic might also be seen. Milder cases appear weak and inappetent. Up to 20% of infected horses can die and survivors become carriers—they carry the parasite even though they aren’t ill. They can, however, pass it to other horses via ticks that bite first the infected horse, then an uninfected one