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Current therapeutic approaches to equine protozoal myeloencephalitis

Levent Dirikolu DVM, MVSc, PhD1, Jonathan H. Foreman DVM, MS, DACVIM2, and Thomas Tobin MVB, PhD, DABT3
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  • 1 Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802.
  • | 2 Department of Clinical Sciences, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802.
  • | 3 Maxwell H. Gluck Equine Research Center, Department of Veterinary Science, College of Agriculture, University of Kentucky, Lexington, KY 40506.

Equine protozoal myeloencephalitis is the most important infectious neurologic disease of horses in the Western Hemisphere. Equine protozoal myeloencephalitis can interfere with a horse's ability to race, work, and perform; untreated, EPM can be lethal. Antemortem diagnosis of EPM is challenging, requiring careful evaluation of the animal's history, clinical signs, and laboratory data, with rigorous exclusion of other causes.

Therapeutic approaches to EPM are evolving. First-generation therapeutic approaches for EPM were based on the classic anti–Toxoplasma gondii pyrimethamine–sulfonamide combinations; treatment is prolonged and can be associated with a considerable relapse rate, which may be associated with the difficulty

Contributor Notes

Supported in part by The National Horsemen's Benevolent and Protective Association; the Alabama, Arizona, Arkansas, Canada, Charles Town (West Virginia), Florida, Iowa, Indiana, Kentucky, Louisiana, Michigan, Minnesota, Nebraska, Ohio, Oklahoma, Ontario (Canada), Oregon, Pennsylvania, Tampa Bay Downs (Florida), Texas, Washington State, and West Virginia Horsemen's Benevolent and Protective Associations; the Florida Horsemen's Charitable Foundation; the Oklahoma Quarter Horse Racing Association; and Neogen Corp.

Address correspondence to Dr. Dirikolu (dirikolu@illinois.edu).