R.M. Nervig
EPM: A Frustrating Disease for Horse Owners
The clinical signs of EPM vary widely among horses. This is because the protozoa can cause damage at various locations in the CNS. The most common signs are: incoordination, weakness, muscle atrophy, and cranial nerve damage. The incoordination and weakness, characteristic of spinal cord disease, are common findings in horses with this disease. The signs involve only one side of the body. Many times what is seen is a weak spastic, swaying, and possibly stumbling gait. Horses can exhibit what appears to be a low-grade lameness. In severe cases, the horses may fall and are unable to get up. The muscle atrophy associated with EPM is not symmetrical and is most apparent over the hindquarters. Cranial nerve damage is manifested by facial paralysis, drooping ear, lazy eyelid, head tilt, and difficulty eating and drinking. Horses with EPM appear bright and alert with no fever. They have a normal appetite, even though they may have problems eating.