Equine Piroplasmosis Found in 15 Wyoming Race Horses

California-positive horse traced to Wyoming; more infected horses found

The Wyoming Livestock Board has issued a press release about a horse health situation in that state which, while serious, is not a public health risk to the general horse population in the state at this time. The full text of the release is printed here for the information of anyone concerned about traveling to or from the state. Racetrack sanctions are possible.

On August 25, Wyoming State Veterinarian Jim Logan was notified by USDA APHIS that a Wyoming origin race horse had tested positive in California for Equine Piroplasmosis (EP), a reportable horse disease. Subsequent testing of other horses in Wyoming that were associated with the positive animal has shown there are 13 additional infected horses involved that belong to one owner in Wyoming as well as another horse belonging to one owner from Utah. 

Soon after receiving news of the infected horse in California, Dr. Logan, along with USDA APHIS and the Wyoming Pari-Mutuel Commission, were able to establish quarantine, testing and movement protocols on the associated horses in Wyoming. These animals are currently under quarantine at the owner’s property.

“We are currently dealing with a horse disease in Wyoming that is specific to race track activities and is not a threat to the general equine population in the state,” said Logan.

Equine Piroplasmosis (EP) is a parasitic infection of equidae that can be spread naturally to equids by ticks or by humans to equids through contaminated needles, syringes, and treatment/surgical equipment and products. The organism that causes the disease is a protozoa named Theileria equi and another strain named Babesia caballi. Clinical signs of the disease are fever, anemia, anorexia, depression, and jaundice. Some infected animals may carry the disease without showing any clinical signs.

Horses affected with Equine Piroplasmosis may be treated under quarantine at the owner’s expense. This is an expensive and very time-consuming process that can take over two years. Other options include lifetime quarantine at a state-monitored location or euthanasia. Dr. Logan and veterinary staff are working with the owner to determine the future disposition of affected animals.

Title 9 of the Code of Federal Regulations prohibits the interstate movement of EP positive equine, but it does not restrict intra-state movement of exposed animals. Therefore, following consultation with the USDA APHIS Equine Epidemiologist, Wyoming Livestock Board (WLSB) veterinarians may allow permitted movement of test negative animals to other Wyoming race tracks this racing season. 

“We are not concerned about horse to horse transmission of this disease,” he said. “The transmission risk of concern is from human (trainer/owner) use of contaminated equipment or product among horses.”

On the advice of Dr. Logan, the Wyoming Pari-Mutuel Commission has issued an order, which will go into effect on September 8, requiring all horses that enter a sanctioned race track in Wyoming to have a negative Theileria equi cELISA test within 12 months prior to the event. Dr. Logan and USDA APHIS are currently working with Director Will Laegreid of the Wyoming State Veterinary Laboratory (WSVL) to enable the lab to conduct testing for EP. This is expected to take about 10 days.

Until WSVL is able to conduct EP testing, veterinarians asked to test horses pursuant to the PariMutuel Commission order can send samples to Colorado State University Laboratory, National Veterinary Services Laboratories or other approved laboratories.

For more information on Equine Piroplasmosis, please contact the Wyoming Livestock Board at 307-857-4140.




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