EPM Horse Disease

EPM horse disease, or equine protozoal myelitis, is a protozoan disease that is acquired by a horse ingesting opossum feces. Discover how EPM can cause damage to a horse's spinal column, causing staggering or unilateral lameness, with information from a veterinarian in this free video on EPM horse disease.

I'm Dr. Gary Garcia of Keystone Equine Associates and we're in Odessa, Florida outside of Tampa. I'm just going to talk briefly on EPM horse disease. EPM Equine Protozoal Myelitis. It's a protozoan disease specific to the horse. It's acquired by horses ingesting opossum feces. The opossum is the intermediate host where the horse is considered the aberrant or dead end host meaning that the protozoan does not propagate any further in the horse but it does cause damage to the horse. As the horse ingests the protozoan the protozoan moves through the vascular system, through the muscles and eventually ends up in the spinal fluid. And can migrate through the spinal chord where it does it's damage. EPM is commonly found almost every state in the United States. Also found in South and Central America. And the testing for EPM initially was through blood testing but now in Florida about 95% of the horses test positive in the blood meaning that they have antibodies for it and have been exposed to it. So what we tend to do now and over the last several years is to test the spinal fluid specifically for antibodies. And that can be done through a spinal tap on the horse either through the atlantal occipital area here by the head and neck or back here in the pelvic area. And that test is called a western blot test. And I implore anyone who has clinical signs of EPM to have the test done before you treat the horse. The treatment can be quite expensive and quite lengthy and quite frustrating at times. Clinical signs of EPM are ataxia which is staggering or wobbling and typically the ataxia is one sided so you may see just a left leg or a right front leg or some sort of unilateral lameness. It can be anything. You can see a see a horse with EPM from anything from just dragging a toe in a very mild lameness to a horse that's flat our recumbent and in a stupor. The clinical signs can vary that much. Horses with EPM can be treated. The treatment can vary in it's successes. Some horses become 100% curable. Some horses retain some neurologic deficits. And yet other horses do not recover and this can also lead to total recumbency and euthanasia of the horse. Some of the older therapies or treatments that were used was sulfadiazene and piromethamine which is a combination treatment. And that treatment lasted, the treatment regiment would go for three to four months minimally. Now we have some newer treatments that last about 28 days with a product called penazoril and in some cases more recent cases in our practice we've used both. Again this is Dr. Gary Garcia at Keystone Equine Associates in Odessa, Florida. We urge you to contact your local equine veterinarian for further information and questions or you can log on to our web site at keystoneequine.com. Thank you.