EQUINE PROTOZOAL MYELOENCEPHALITIS

Equine protozoal myeloencephalitis (EPM) is a common neurologic diseas e of horses in the Americas. Horses with EPM most commonly have abnorm alities of gait, but they also may present with signs of brain disease . The disease ranges in severity from mild lameness to sudden recumben cy, and clinical signs usually are progressive. A causative agent, Sar cocystis neurona, has been isolated from affected horses, and serologi c surveys suggest that approximately 50% of horses in the United State s have been exposed. EPM is considered a treatable disease, although t he response to antimicrobial treatment often is incomplete. This artic le highlights new information about the life cycle of S. neurona and r eviews the literature regarding diagnosis, clinical signs, and treatme nt of the disease.