Written By: Annette McCoy, DVM, University of Minnesota College of Veterinary Medicine
What is equine protozoal myeloencephalitis (EPM)?
EPM is a disease of the central nervous system (brain and/or spinal cord) that is caused by the protozoal organism Sarcocystis neurona. The main host for this organism is the opossum and horses that are exposed to opossum feces with infective sporocysts can develop neurologic disease. Other hosts of S. neurona include armadillos, skunks, and domestic cats; however, these animals cannot directly transmit the disease to horses.