Higher Education

Equine Protozoal Myeloencephalitis (EPM): Resources for Information

By Ashley Phelps, DVM

Dr. Ashley Phelps has over 10 years of field experience as an equine veterinarian. She holds her Doctorate of Veterinarian Medicine from Mississippi State University and in her spare time enjoys doting on her horse, Ava.

Equine Protozoal Myeloencephalitis (EPM) is a challenging neurological disease caused by Sarcocystis neurona and Neospora hughesi, which can manifest in many ways. Most often clinical signs include:

Ataxia (incoordination), spasticity (stiff, stilted movements), abnormal gait or lameness
Incoordination and weakness that worsens when going up or down slopes or when head is elevated
Muscle atrophy, most noticeable along the top line or in the large muscles of the hindquarters, but can sometimes involve the muscles of the face or front limbs
Paralysis of muscles of the eyes, face or mouth, evidenced by drooping eyes, ears or lips
Difficulty swallowing
Seizures or collapse
Abnormal sweating
Loss of sensation along the face, neck or body
Head tilt with poor balance; horse may assume a splay-footed stance or lean against stall walls for support.

Research is still ongoing to understand this disease better and why some horses develop clinical signs and others do not, despite most horses in the United States being exposed. Diagnosis and treatment of EPM possesses many challenges as well. Below are resources on diagnosis, treatment and ongoing research regarding EPM.




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