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Equine Protozoal Myeloencephalitis(EPM)

EPM is a neurological disease in equines (horses, donkeys, etc) that is caused by single cell parasites called protozoa. These protozoa are most often shed in the feces of opossums (Sarcocystis) but occasionally in the feces of dogs (Neospora) and are ingested by the horse on grass, hay, feed, or in water.  For most horses this does not cause problems but in some horses these protozoa are able to cross into the brain.  Their presence in the brain causes progressive neurological disease - initially vague symptoms that progress to more severe problems ending in death.  Successful treatment requires early detection and aggressive treatment.

EPM cases are skyrocketing in coastal Georgia in the last 6 months and something owners need to be aware of, monitor for, and treat aggressively when detected.

Vitamin E deficiency is strongly associated with EPM.  Unfortunately, with the soil and natural grass type in coastal Georgia, Vitamin E deficiency is very common increasing the risk of EPM developing in exposed horses.

Initial signs are very vague and often attributed to "attitude" or "aging changes". Here are some of the more commonly observed signs:

(1) Changes in "behavior" when riding:   Resistant to turning, forging/rushing uphill, lagging/resistant to moving quickly,  "acting" up especially on physically demanding rides

(2) Changes in eating- sloppy eating with dropped food, choke especially recurrent episodes

(3) Changes in body - lips are more limp and less responsive to touch, loss of body condition in topline, neck, along ribs, then in limbs

(4) Weight loss even with increased calories

(5) Changes in "energy"- tire more easily, head held down more often, eyes seem dull and distant, move around less often, walk around in a "daze"

(6) Reduction in strength/stamina - move away, lean, fall when saddling, mounting and/or grooming, able to pull to side with gentle tail tug when walking and/or standing

(7) Changes in gait - dragging feet, swinging feet out when stepping, lameness that changes in location and severity,  frequent stumbling

As it progresses the horse becomes unable to eat, starts pacing, becomes unable to stand/walk or starts compulsive circling that cannot be controlled/stopped.  If left untreated most end up humanely euthanized due to loss of quality of life.

It is very important to know these early vague signs as many can be overlooked as "stubborn", "aging changes", etc.  Treatment is typically successful if caught early; the later it is diagnosed the more likely euthanasia will be needed.

here for a video on evaluating neurological health in a horse.  EPM can cause a wide variety of neurological abnormalities.

           (1) Supplement Vitamin E - 5000IU per day
           (2) Feed High quality pasture/hay
           (3) Protect food via metal containers, keeping in an enclosure, etc
           (4) Eliminate/reduce opossum presence around horses

Treatment includes high levels of Vitamin E and antiprotozoal medications like Marquis.

Check your horses often and have them evaluated (see equine vets in area below) for EPM if there is any doubt.

Area Equine Veterinarians
Countryside Equine Medicine and Dentistry  912-247-2834
    (2) Wolfe Animal Hospital (Wayne County),  912-427-3212
  (3) Pine Harbor Animal Hospital,  912-832-2315
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