A review of Sarcocystis neurona and equine protozoal myeloencephalitis (EPM)

Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in the Americas, The protozoan most commonly associated with EPM is Sarcocystis neurona. The complete life cycle of S, neurona is unknown, i ncluding its natural intermediate host that harbors its sarcocyst, Opossums (Didelphis virginiana, Didelphis albiventris) are its definitive hosts. Ho rses are considered its aberrant hosts because only schizonts and merozoite s (no sarcocysts) are found in horses. EPM-like disease occurs in a variety of mammals including cats, mink, raccoons, skunks, Pacific harbor seals, p onies, and Southern sea otters. Cats can act as an experimental intermediat e host harboring the sarcocyst stage after ingesting sporocysts. This paper reviews information on the history, structure, life cycle, biology, pathog enesis, induction of disease in animals, clinical signs, diagnosis, patholo gy, epidemiology, and treatment of EPM caused by S. neurona. Published by E lsevier Science B.V.