EPM Diagnostic Test Developed for Horses

Equine protozoal myeloencephalitis (EPM) is a degenerative neurological disease that affects horses. First described almost 40 years ago, the disease is one of the most commonly diagnosed equine neurological disorders in the United States. A recent study by the USDA showed an incidence of 14 new diagnoses of EPM per 10,000 horses per year in the United States. While this number refers to horses that actually have EPM, between 22% and 65% of horses in the United States have developed antibodies to Sarcocystis neurona, the protozoal parasite that is the most common cause of the disease.

To infect horses, the protozoan must move into the central nervous system from the blood.  Several theories have been developed concerning why some exposed horses go on to develop clinical disease while others do not, but the reason is not known.

A new diagnostic test for equine protozoal myeloencephalitis (EPM) has been developed by a team led by Daniel Howe, Ph.D., at the University of Kentucky‘s Gluck Equine Research Center. The diagnostic tool measures the antibody response of horses to immunogenic proteins located on the surface of Sarcocystis neurona. By comparing the amount of antibody present in the horse’s blood to the level in its cerebrospinal fluid, it is possible to verify with a high degree of accuracy whether the horse is actually suffering from EPM or has simply been exposed to the parasite.