EPM and Horses: 9 Fast Facts

Last Updated on February 21, 2022 by Allison Price

Horses continue to be affected by Equine Protozoal Myeloencephalitis (EPM). This causes neurological deficits that can threaten their athletic careers as well as their lives. EPM is still a challenging diagnosis and can be difficult for others to distinguish from neurological diseases. To minimize infection , you will need to improve your knowledge *,**,of the disease.

EPM and Horses
  • EPM is caused by infection with either Sarcocystis neuralna oder Neospora Hughesi parasites. S. is the most common topic. neurona, as there is less information on N. hughesi is currently available.
  • Many horses have antibodies against S. neurona. This means that horses were exposed to the parasite but infection did not occur. The parasite can be fought off by the immune system, even if there is no evidence of active infection.
  • Horses can become infected from eating opossum feces that contain S. neurona. The parasite then moves through the horse’s body, before becoming a part of the central nervous system (CNS), which is the brain and/or spinal chord. Each parasite “lands” in its own part of the central nervous system (CNS). This means that each horse with an infection will have unique clinical signs.

“Creating an opossum-free pasture may be difficult for many equine operations. However, feeding off the ground, and keeping opossums out of the barn and feed room by making sure hay, concentrates and other feeds are kept out of reach, and sealed in tight-fighting lids on bins will help reduce exposure to S. Kathleen Crandell (Ph.D.), a nutritionist at Kentucky Equine Research (KER), advised neurona.

  • EPM can present in many ways, including weakness, seizures, increased reflexes, depression and head tilt.
  • EPM is still a “diagnosis for exclusion.” This means that any other neurologic diseases must be excluded before a presumptive diagnosis can be made. EPM can be diagnosed with absolute certainty using all available tests. However, necropsy is the only way to visualize the parasite in the CNS.
  • One of the three FDA-approved drugs may be used to treat horses presumptively diagnosed as having EPM.
  • Other treatment options include compounded medication (e.g. decoquinate and levamisole) as well as anti-inflammatory drugs like flunixin meglumine or DMSO.
  • Secondary oxidative damage can also occur, which is why vitamin E has been recommended for horses with EPM.

Experts recommend giving horses with EPM between 5,000 to 10,000 IU of natural Vitamin E each day. Crandell shared that Nano*E is a water-soluble, fast-absorbing form of vitamin E recommended by veterinarians to horses suffering from EPM.

  • Horses treated for the parasite may have residual neurological symptoms.
Allison Price
Allison Price

I’m Allison, born and raised in San Diego California, the earliest memory I have with horses was at my grandfather’s farm. I used to sit at the stable as a kid and hang out with my Papa while he was training the horses. When I was invited to watch a horse riding competition, I got so fascinated with riding!