Horse on Contact Premises Positive for Piroplasmosis

According to an Aug. 25 statement from the Florida Department of Agriculture and Consumer Services (DOACS), a horse on a second property has tested positive for equine piroplasmosis.

Florida Agriculture and Consumer Services Commissioner Charles H. Bronson announced Aug. 15 that a horse in Manatee County, Fla., had been diagnosed with equine piroplasmosis, an animal disease that the U.S. has been considered free of since 1988.

The affected horse was euthanized, but since that time, four other horses on the original property tested positive for the disease.

Several adjacent and contact premises linked to the original positive property have also been investigated. Of the 30 additional horses tested late last week, one horse from a contact premises tested positive, the DOACS said in an official statement

State officials are working with the USDA to continue the investigation. This work includes identifying additional horses or premises that might have been in contact with or associated with a positive horse or premises.

Representatives of the Southeastern Cooperative Wildlife Diseases Study are assisting with tick surveillance on affected premises.

Equine piroplasmosis (EP) is a tick-borne disease caused by two parasites, Babesia caballi and B. equi. The parasites are able to hitch a ride on certain ticks, in which they can amplify, thus, creating the potential for spread to horses. The parasites can also be spread via shared needles.

According to Mike Short, DVM, equine programs manager for the DOACS, it seems most likely that the disease was passed on the original property via shared needles and other management practices used there.

Piroplasmosis occurs through much of the world. Areas not considered endemic include the United States, Canada, Australia, Japan, England, Iceland, and Ireland. Horses that get EP might have a fever, anemia, jaundice, hemoglobinuria (the presence in urine of a protein normally found in red blood cells), central nervous system disturbances, and they sometimes die. But some infected horses are less severely affected and might show few or no clinical signs. These horses have the potential to carry the parasites for prolonged periods, during which they are potential sources of infection.

To prevent EP from entering the country, the USDA currently tests all imported horses for antibodies during quarantine. Horses with antibodies to B. caballi and/or B. equi are not allowed entry into the United States.

The only current treatment is a potent type of chemotherapy that should eliminate clinical signs of disease; however, it won't necessarily eliminate the parasites from infected horses.

With the exception of the quarantined premises, there are no equine movement restrictions in Florida or between Florida and other states. As of Aug. 21, Canada has advised the United States Department of Agriculture they will not accept horses originating from Manatee County, effective immediately. Horses entering Florida from countries with equine piroplasmosis will continue to be tested prior to and following entry, in accordance with the current rule.

Horse owners are asked to report any unusual clinical signs to their veterinarians, and to use commercially available topical tick repellent products if your horse is in an area where ticks are a problem. Include an avermectin product in your deworming program to provide systemic treatment for ticks.

Horse owners are also reminded not to reuse needles among different animals while administering any medications or vaccinations.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care. She owns a portly gray gelding named Duncan and dabbles in several equestrian disciplines, with an emphasis on dressage.

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