Horses contract EPM by ingesting the organism protozoal. Protozoal is a parasite found in infected feed, water, hay, or pastures. The horse‚Äôs food source becomes infected by opossum feces that contain the sporocysts parasites. It is important to point out that the parasite can only be passed to horses from opossums. The parasite cannot be transmitted from horse to horse, or from any other animal to the horse.
When a horse ingests the infected feed they become carriers. Once the sporocysts parasites make their way to the intestinal track they travel into the blood stream. They follow the blood stream to the blood-brain barrier and begin to attack the central nervous system.
The severity of the disease can be linked to four factors: the amount of parasites ingested, the length of infestation prior to treatment, the location where the parasites settle and the amount of stress a horse is under during or after infestation.
EPM is treatable, and as much as 70% of horses will show dramatic improvement or become symptom-free after aggressive treatment. Currently there are two drugs available to treat EPM. Treatments last from 1-6 months and can be expensive. There are a percentage of horses that will relapse; estimates are between 10-20%.
Treatment protocols don‚Äôt come without risk. Although rare, it may affect stallion fertility causing potential health risk to foals. Other side effects include anemia, low platelet count, and low white blood cell count. Blood work will generally be done during treatment to monitor for these blood abnormalities. You will also want to watch for diarrhea.
Catching the signs of EPM early will give your horse a better change at recovery. Make yourself familiar with the Symptoms of EPM.
You can call our clinic (636.332.5373) and we will be happy to perform a neurological exam on your horse. If we see any signs of EPM we will run blood and cerebrospinal fluid analysis to verify your horse has been exposed and work with you to develop a treatment plan.