The results of a study which reveals a high mortality rate in horses with tick paralysis was presented May 27 at the Australian Veterinary Association’s 2013 annual conference.

Mick Ruppin, BVsc, one of the study co-authors, said that prior to 2012 there was limited information published about tick paralysis causing the deaths of horses.

“The paralysis tick is found predominantly along the east coast of Australia, in high rainfall areas, ” Ruppin said. “Our study was a retrospective analysis of cases treated at our practice on the east coast of Queensland over the last ten years, as well as cases treated at other practices along the east coast over the last five years. A total of 103 cases were analyzed.

“The number of paralysis ticks required to paralyze a horse is unknown, but our study included cases where large horses with only one to two ticks were paralyzed and unable to stand,” he said. “Horses of any age and size can be affected by tick paralysis.

“The mortality rate of 26% in horses is much higher than the mortality rate in small animals which is around 5%” Ruppin continued. “In our study, 26% of the horses died and of the surviving horses, 35% developed one or more complications including pressure sores, corneal ulcers, pneumonia, and sepsis.”

Ruppin said that higher mortality rates in horses could be due to a range of factors including horses being badly affected before veterinarians are called; difficulties associated with nursing a recumbent horse; difficulties with owners needing to deliver the bulk of nursing care; and lack of information to veter