The World Organization for Animal Health reported on June 11 an outbreak of equine piroplasmosis in Jackson County, Mo. The last reported occurrence was in February.
EP is a tick-borne disease that affects horses, donkeys, mules and zebras. The disease, caused by Theileria equi, is transmitted via tick bites or through mechanical transmission by improperly disinfected needles or surgical instruments, according to the U.S. Department of Agriculture's Animal and Plant Health Inspection Service.
The source of the most recent outbreak was deemed “unknown or inconclusive.”
The affected premises is a horse stable in Jackson County involving a 7-year-old quarter horse gelding purchased six months ago. The horse showed clinical signs consistent with EP on June 1.
The next day, the horse was presented to a veterinary medical hospital in Kansas because of an acute illness consistent with infection of a blood-borne pathogen. The horse was placed in quarantine and isolation.
The horse and other animals on the affected premises — 63 including horses, ponies and mules — were examined for ticks. No ticks were found, according to the OIE report.
Test results for the other animals are pending, and the premises remains under quarantine.
The epidemiological investigation is being conducted by the Animal and Plant Health Inspection Service in conjunction with the Missouri Department of Agriculture.