EPM is becoming an all too familiar disease to many horse owners in our practice and across the country. The cause of this disease is a parasitic protozoan, a microscopic, single celled organism called Sarcocystis neurona. When ingested, this protozoan sometimes finds its way into a host horse�s spinal cord causing inflammation and eventually nerve cell damage.

Early clinical signs of this disease include: falling, or peculiar hoof placement. An advanced disease can be seen as marked incoordination, toe dragging, lameness, inability to chew and/or swallow, blindness, seizures and paralysis.

Diagnosis of EPM is based on presence of clinical signs along with analysis of a blood sample and cerebral spinal fluid (CSF). A positive blood test indicates a horse has been exposed to the parasite, but not that he necessarily has the disease. A positive CSF test along with clinical signs confirms the diagnosis and warrants a treatment.

In the past several years there has been a tremendous effort in researching this disease. What has been determined thus far: * EPM can affect horses of any age, breed or sex * There is no vaccine for EPM * EPM can�t be passed from horse to horse * Horses acquire EPM through pasture/hay, grain and water that has been contaminated with opossum feces containing Sarococystis neurona * Contamination of feed or water with opossum feces may occur indirectly through birds or insects as well as directly through opossums * Early detection and treatment increase the chances of recovery

If you are concerned about your horse�s potential exposure to the disease, I recommend you attempt to rid your pastures and stable areas of opossums through humane measures. Keep feed bins and water receptacles clean and rodent proof.

It�s important not to panic. Because testing is expensive, it isn�t recommended routinely. Nevertheless, if you see your horse exhibiting any of the signs above, be sure to call your vet. Symptoms of EPM are similar to other diseases and a veterinarian should examine the animal to determine if testing is needed.