What are Equine Protozoal Myeloencephalitis?
The spores of a protozoal parasite that cause equine protozoal myeloencephalitis will migrate from the intestinal tract into the bloodstream and cause severe illness. Your horse’s central nervous system is then affected and if left untreated can cause lasting and severe neurological damage. Once the disease has progressed to where neurological issues are present, that is indicative of lesions forming in the brain, on the brain stem or the spinal cord.
Equine protozoal myeloencephalitis or EPM is a very serious disease that can oftentimes mimic other health problems in horses. Your horse’s symptoms can range from mild to severe, making it difficult for veterinarians to properly diagnose EPM right away.
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Symptoms of Equine Protozoal Myeloencephalitis in Horses
The symptoms of equine protozoal myeloencephalitis are varied. The symptoms will greatly dependent of the severity of the lesions that have developed in the brain, on the brain stem or the spinal cord. Symptoms may include:
- Stiff or stilted movements
- Abnormal gait
- Incoordination or weakness, especially when the head is elevated
- Muscle atrophy, especially in the hindquarters or along the topline
- Paralysis in the face or mouth
- Drooping eyes, ears or lips
- Difficulty swallowing
- Excessive sweating
- Loss of feeling in the face, neck and body
- Splay footed stance or leaning against objects for support
Causes of Equine Protozoal Myeloencephalitis in Horses
An organism that is a protozoal parasite, Sarcocustis neurona or Neospora hughesican, causes equine protozoal myeloencephalitis. The organisms are spread by a host, most likely the opossum, who drops spores through their feces. When a horse comes in contact with the infected feces, they are then exposed to the protozoal parasite. The exposure can occur through grazing or eating contaminated feed or drinking contaminated water. There are several factors that influence the progression of equine protozoal myeloencephalitis. Of these influences, there are four that are the most important.
- The number of organisms that have been ingested by your horse
- The length of time that your horse harbors the protozoal parasite before treatment is sought
- Where in the brain or the spinal cord the protozoal parasite has localized and damage occurred
- Any stressful events that follow the infestation
Diagnosis of Equine Protozoal Myeloencephalitis in Horses
Clinic symptoms of equine protozoal myeloencephalitis will mimic other neurological diseases in horses. Your veterinarian will first need to do a full physical examination. EPM tends to affect one side of the horse more than the other side, so your veterinarian will be looking for any asymmetrical symptoms to help make a diagnosis.
Blood tests and cerebrospinal fluid analysis will tell that your horse has been exposed to a parasite. This will allow your veterinarian to begin giving aggressive treatments to stop the progression of the parasite within the blood stream and brain.
Treatment of Equine Protozoal Myeloencephalitis in Horses
Immediate treatment is extremely important once symptoms present to give your horse a better chance of recovery. Aggressive treatments have proven effective in reversing symptoms of EPM allowing many horses to return to normal activities.
Only medications that have been labeled by the FDA to treat EPM are to be used when your horse has been diagnosed with EPM. Your veterinarian will prescribe the appropriate anti-protozoal medications for your horse.
These may be used to prevent reactions to the parasites as they die off during treatments and to alleviate symptoms to make your horse more comfortable.
Your veterinarian may recommend adding vitamin E to your horse’s diet. It is an antioxidant and is many times used to aid healing of nervous system tissues.
Depending on how depleted your horse has become, intensive care including IV therapy may be necessary to keep your horse hydrated during treatments. Your veterinarian will lay out a full treatment plan for you, including supportive care.
As your horse undergoes treatment be sure to keep your veterinarian informed of any changes that you see in your horse. Treatments may need to be adjusted to fit your horse’s needs.
Recovery of Equine Protozoal Myeloencephalitis in Horses
Immediate, aggressive treatments will help your horse fight EPM and hopefully reverse any effects that the protozoal parasite may have caused allowing your horse to return to a normal routine. Complete all follow up care that your veterinarian has outlined in your horse’s care plan to ensure that your horse is indeed on the road to recovery.
Prevention is also important. Keep rodents and especially opossums away from feed rooms and out of hay or bedding. Use feeders to minimize spillage and keep rodents and wild animals out. Clean up dropped grain immediately. Feed your horse heat-treated cereal grains and extruded feeds; this will ensure that any infected spores have been killed. Also, schedule routine veterinarian visits and keep vaccinations and dewormings current.