Tick-borne Diseases in Horses in the Eastern United States

Borrelia burgdorferi infection in horses is common in some areas of North America, yet the incidence of clinical disease has not been determined which makes Lyme disease in the horse controversial. Progress is being made, case-by-case, in defining the several clinical presentations of Lyme disease in adult horses. Current serologic tests are very sensitive and specific for detecting either previous or concurrent infection or exposure but may not distinguish between those. Treatment protocols are available for Lyme disease in the horse, however, their ability to eliminate the organism remains questionable. Currently, minocycline is being tried in some presumed Lyme cases as a possibly improved alternative to doxycycline and oxytetracycline. Vaccination, like many aspects of Lyme disease, remains controversial, although the canine approved vaccines have the potential to prevent infection based upon vaccine studies in ponies and other animals.