The symptoms of EPM vary from case to case. Knowing what is “normal” for your horse can go a long way in recognizing a problem and catching it early. If you suspect your horse has EPM, look for the following signs.*
- Lack of coordination, which may worsen when going up or down a hill or when the head is elevated.
- Stiff or stilted movement
- Abnormal gait or lameness
- Muscle atrophy. This is generally noticeable along the top line or around the large muscle in the hind end. Occasionally it can affect the muscles in the front limbs and face.
- Paralysis of the eye, faces, or mouth muscles. You may notice drooping eyes, ears, or lips.
- Trouble swallowing
- Seizures or collapse
- Abnormal sweating
- Loss of feeling in the body, neck or face
- Poor balance
- A horse may lean against its stall walls for support, or may stand splay-footed (feet turned out)
* We should point out in many cases the symptoms are asymmetrical and will only affect one side of the body.
There are four contributing factors that seem to determine the severity of EPM. They are:
- The number of parasites that the horse ingested: the larger the number of parasites, the more severe the symptoms
- The amount of time a horse is infested with the parasites prior to treatment
- The location of the organisms: brain, brain stem, or spinalcord
- If the horse experiences a stressful event during or after infection
If you suspect your horse may have EPM, your veterinarian will perform a standard neurological examination. If they identify a symptom, they may order blood and cerebrospinal fluid analysis that will determine your horse’s exposure to EPM.
Learn more: How Horses Contract EPM