Depending on the region you live in, EPM (Equine Protozoal Myeloencephalitis) can be a common or rare occurrence among horses and can range widely in disease severity and symptoms.
While many horses are exposed to the protozoan organisms that cause EPM, only a small percentage will develop the disease and be symptomatic.
If you suspect your horse might have EPM or your horse was recently diagnosed, there are things you can do to get ahead of the disease progression and support your horse while they recover from EPM.
In this guide, you will gain a deeper understanding of what EPM is, the symptoms of a horse with EPM, and how to treat horses with EPM both naturally, nutritionally, and medically.
What is EPM in horses?
Equine Protozoal Myeloencephalitis (EPM) is an infectious disease that affects the central nervous system in horses and is caused by a protozoan organism.
The most common protozoan organism that causes EPM in horses is Sarcocystis Neurona, and less commonly is the Neospora Hughesi protozoa.
Sarcocystis Neuronais is transmitted by the horse ingesting feed, hay, or water contaminated with EPM affected opossum feces, while the host of Neospora hughesi is still unknown at this time.
Transplacental transmission of the Neospora Hughesi protozoa that results in EPM infected foals has also been documented, although not for the Sarcocystis Neuronais protozoa.
How is EPM in Horses Diagnosed and What Are the Symptoms?
Unfortunately, EPM diagnoses can be tricky, and symptoms can often mimic other conditions. A definitive diagnosis can only be made through postmortem detection of the protozoa.
However, many vets can make an educated suspected diagnoses by looking at the presented neurological symptoms that align with EPM or by doing a cerebrospinal fluid serum (CFS) test. They may also rule out other neurological diseases with similar symptoms first, such as wobblers, Lyme disease, rabies, or Cushing’s disease to further evaluate if it’s truly EPM.
Despite years of significant research, there is still so much that is unknown surrounding EPM. Because the protozoa that cause EPM can infect any part of the central nervous system, this means technically any neurological sign is possible.
Typical symptoms for EPM in horses involve the spinal cord, and a common one is asymmetrical or symmetrical weakness, atrophy, and ataxia of the muscles. The hindquarters and topline are common muscling areas for these signs, and many times it’s worse on one side versus the other.
Other symptoms include lethargy, vestibular signs like a head tilt, leaning, drooping ears, dropping feed, trouble swallowing, abnormal eye movements, unusual sweating patterns, sore back, and overall poor balance, incoordination, or lameness.
Symptoms can have a gradual progression, or they may progress rapidly.
Since EPM can be life-threatening, having your horse examined by a veterinarian should you suspect even subtle signs of EPM is vital.
Relapse of EPM within 1-3 years after treatment can occur in about 10% of affected horses.
Treatment for EPM in Horses
EPM is treated with anti-protozoal medication, which is often paired with supportive rehabilitation care and medicines like anti-inflammatories.
The three FDA-approved treatments currently available for EPM are Ponazuril (Marquis), Diclazuril (Protazil), Sulfadiazine and Pyrimethamine (Re-Balance).
These medications limit reproduction and kill off the EPM causing protozoa. The treatment works by reducing the protozoa numbers to the point that the horse’s immune system can hopefully resolve the disease from there. For this reason, immune system support is important for EPM affected horses.
The exact treatment plan will be developed with your veterinarian specifically based on your horses EPM symptoms and disease severity.
In addition to your horse’s prescribed medical treatment, there are some nutritional strategies you can do to help support your horse during their EPM recovery and help treat EPM naturally
If your horse has already been diagnosed, your vet has likely mentioned the benefit of a Vitamin E supplement for horses with EPM.
This is because natural Vitamin E is a potent antioxidant that supports nerve function and the immune system. Levels of at least 5,000 to 10,000 IU per day are recommended during EPM treatment in horses. Vitamin E levels in a horse’s blood can be monitored and the amount that is fed can be adjusted for longer term use at higher levels, if necessary.
A nutritionally balanced diet that meets the horse’s other vitamin and mineral needs is very important when a horse has EPM. This is because there are many essential nutrients that are involved in supporting the immune system beyond Vitamin E.
Since muscle atrophy is a common symptom of EPM in horses, supporting muscle rebuilding with a focus on high quality protein in the diet is key. Providing quality protein is achieved by feeding higher levels of lysine, methionine, and threonine.
Essential K® or Wholesome Blends® Balancer are a great nutritional way to support horses in many ways during EPM recovery. Both products are highly concentrated in essential vitamins, minerals, and high-quality amino acids needed for things like muscle rebuilding.
During EPM recovery, you can add an additional 2 lbs. per day total of either ration balancer for an extra boost of nutrients. If your horse is on a full intake horse feed (one designed to be fed at 4+ pounds per day), add 1 additional pound of Essential K® or Wholesome Blends® Balancer on top of their regular horse feed.
Many horses with EPM experience significant weight loss, so they may need support with weight gain as they recover. A high-fat supplement like K-Finish provides healthy additional calories with ingredients like full-fat soybeans, flaxseed rice bran, and omega fatty acids. This will also help with the poor hair coat they might experience due to EPM.
Because EPM is an inflammatory disease, Natural Remedy, a natural anti-inflammatory supplement, has ingredients like DHA and omega-3 fatty acids that help naturally reduce this inflammation. It also has the added benefit of supporting immunity, heart, and respiratory functions.
If your horse has been diagnosed with EPM, Tribute Nutrition can help you develop a personalized feeding plan for the treatment period, recovery stages, and for when they are back to normal.
