Tick Paralysis Bad News for Horses

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 veterinarians treating the disease in horses.

“Given the difficulties associated with treating tick paralysis in horses, prevention is the best option for horse owners,” he said. Prevention strategies include:

  • Reducing exposure to ticks by keeping horses in shorter pasture, away from bushland;
  • Checking horses daily for presence of ticks and clinical signs of tick paralysis; and
  • Using sprays and other products that can offer some protection from ticks.

“If horse owners find ticks or see signs of tick paralysis it’s important that they contact their vet immediately,” Ruppin said. “The earlier treatment is provided, the better the result.”

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