Lyme Disease education

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Lyme disease is induced by the spirochete B. burgdorferi. Spirochetes are transmitted to horses by infected ticks. Similar to humans, horses are incidental, dead-end hosts for B. burgdorferi1. Not all infected horses develop clinical signs of Lyme disease. If clinical signs occur, they can include chronic weight loss, sporadic lameness, shifting leg lameness, low-grade fever, muscle tenderness, chronically poor performance, swollen joints, arthritis and diverse orthopedic problems2-5. Changes in behavior and skin sensitivity (tactile hyper-aesthesia), both with rapid onset, are common clinical signs seen by many practitioners in horses with potential Lyme disease. Neurological signs such as depression, dysphagia, head tilt and encephalitis were reported in chronic cases2,6,7. Most recent reports describe horses with a Borrelia-associated pseudolymphoma8 or Borrelia-associated uveitis9.

Even though horses often show improvement within days of the beginning of treatment, Lyme disease is as hard to get rid of in horses as it is in humans. It is important that medications be given as ordered and all the meds need to be given, even if the horse seems to be better. The horse will need to be re-tested several times over the course of the next year. If your horse has chronic Lyme disease you will have to treat the symptoms as they appear.

The old horseman’s cure-all of a good grooming every day to catch early signs of other problems may be your best defense against Lyme disease. Pay particular attention to the base of the tail, the mane up to and including the area around the ears and throatlatch and all of the underbelly. Using fly sprays that include permethrins will also help to discourage ticks, as will keeping down high brush or grasses in the turn-out area.