EMP

EPM Status Report
By: Joanne Meszoly
Equus

EPM stands for equine protozoal myeloencephalitis. This article is about an exclusive interview with Robert MacKay, BVSc, PhD, of the University of Florida’s large animal medicine section. The first topic discussed was about the animal that carries the parasite responsible for EPM. They have come to the conclusion that the opossum it the main host of the parasite Sarcocystis neurona. There are also intermediate hosts such as the cat, raccoon, skunk, armadillo and the sea otter. It starts out with the opossum eating the flesh of an intermediate host, over several weeks the organism grows in the opossum’s intestines and produces eggs. They then release sporocysts that go out with the feces and into the environment. The horse ingests the sporocysts in water of food and once they hatch they release sporozoites which raid the horses intestinal wall. They then travel in the blood to the lungs or liver where they begin replicating. At this point, a normal horse’s immune system will usually take care of the infection, but in some horses the parasites continue to multiply and work their way, through the blood to the brain where they settle in the cells of the central nervous system, causing lesions to form on the spinal cord and sometimes on the brain. The most common sign for EMP is weakness in the hind muscles and loss of coordination. EPM is can be treated several different ways, one by a drug called ponazuril, or a 28-day oral paste called nitazonanide. Usually, depending on the severity of the disease, less than one in five horses will completely recover from EMP. It seems that it is very hard for horses to completely get rid of the infection, in some cases it’s something they have for life. Ways to keep your horse from getting EPM are to make sure you secure grain storages and keep water tanks clean. Also checking your pasture for remains of dead cats, armadillos, skunks and raccoons will help prevent opossums coming around.

This status report isn’t very good news and I think it is something we should be concerned about. At this point researchers are working on new vaccines for EPM, and I believe we should keep working toward learning more about S. neurona. But again this disease isn’t that common, because most horse’s immune systems will fight the infection, still this is very important to certain people. It affects the natural world in many ways because not only could S. neurona affect horses is could also affect other grazing animals such as sheep, goats, and cattle. If this parasite gets does infect cattle we could have problems with one of our meat sources. So in many ways this article only pertains to horse owners, but in other ways it could affect beef eaters all around the world.

This article is very factual and I have learned a lot about EPM, what causes it, and how to prevent it. I would definitely recommend people who own horses or horse farms to read it because it mainly applies to them. Others may read it too, but if they don’t do much with horses it may not be as relevant to them. So attention barn managers and horse owners everywhere, this article can teach you how to look for EPM and prevent it.