Note: If your horses are in Tennessee or if you are planning to take horses into or through Tennessee, you should keep up with information about horse transport restrictions, in the event that any are initiated related to this outbreak. At this time, no known restrictions are in place.
Seventeen racing Quarter horses in Middle Tennessee have tested positive for equine piroplasmosis (EP). The State Veterinarian and the University of Tennessee College of Veterinary Medicine have issued warnings to horse owners to educate them about how horses contract the disease, and to keep them up to date on the situation.
The State Veterinarian said that all 17 horses are connected to the same location in Rutherford County, Tennessee.
The following information about EP was provided by the State of Tennessee’s Department of Agriculture:
EP is a blood parasite that affects equines. Although it can be transmitted through infected ticks, today it is more commonly spread by blood and blood products through the sharing of needles, syringes or improperly cleaned and disinfected dental, tattoo, surgical or blood product equipment between infected and uninfected horses.
It may take as long as 30 days for an infected horse to test positive for the disease after exposure.
Early clinical signs can range from weakness and lack of appetite to swelling of limbs and labored breathing. Horses that survive the acute phase continue to carry the parasite for an extended period of time.
Horses that test positive for the disease are quarantined and may be euthanized. Horses will not transmit the disease to other horses through casual contact. However, it is critical that horse handlers practice good biosecurity. If a needle is required, use a new sterile needle and syringe on every horse and clean and disinfect all equine equipment that may be contaminated with blood.
Learn how to protect your horses from EP. Some states and equine competitions require EP testing for entrance.
If you plan to travel with your horse, check with the receiving state for current import requirements.
The University of Tennessee College of Veterinary Medicine added a report about the outbreak and included information on the disease, with this background on the importance of reporting equine piroplasmosis:
“In efforts to try to prevent this potentially devastating disease, horses imported into the United States are quarantined and tested for evidence of piroplasmosis and the causative organisms.
"Prior to 2005, imported horses were tested using a complement fixation test, however, it has been found that this test has low sensitivity for chronic carriers of piroplasmosis; therefore, some carriers could be missed when imported into the country. Because of this, it is possible that some horses imported into the U.S. prior to 2005 may be, or have been, carriers and, therefore, infected horses may be in the country today.
"Currently, imported horses are tested using a more reliable cELISA test that is more sensitive for chronic carriers.
"If a horse in the United States is suspected of having piroplasmosis, the veterinarian is required to contact and report the case to state or federal authorities (APHIS). In addition, the horse must be quarantined and prevented from having contact with ticks, or, in some cases, the horse may be euthanized.
"In cases of international equine events or competition, infected horses may be allowed to compete, but very stringent precautions have to be taken to make sure that contact between infected horses and ticks is prohibited, especially when an infected horse is allowed into a non-endemic area, such as the United States.
"Currently, there is not a vaccine for piroplasmosis and prevention is important. Preventive measures include testing of imported and exported horses, eliminating or preventing contact with ticks, timely removal of ticks found on horses, and preventing transmission of blood between horses by not sharing needles among horses and properly sterilizing and disinfecting equipment."
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