EQUINE PROTOZOAL MYELOENCEPHALITIS


EPM Early Rehabilitation Summary

This phase of EPM will require more owner input than any other time during testing, treatment, or recovery.  Each horse will have nerve damage in a different area, and to a different severity.  There is no perfect rehabilitation protocol useful for all horses; the owner and veterinarian have to consider each individual case to create a plan.  Decisions about turnout, exercise, vaccines, wormers, and riding should be based on ‘what the horse is telling you’.

Three different horses grazing together - 'Friends are one of a kind'
   © EPMhorse.org   Friends are one of a kind
One of the hardest parts for the owner to understand is that the horse has deficits in the central nervous system that may take up to a year to heal.  The analogy of a human stroke victim, with partial paralysis, is often used to describe an EPM horse.  The horse may not be able to complete certain moves because the brain does not have a connection to the muscle necessary for the movement.

It is important for the owner to base rehabilitation work on the needs of the horse.  The human must set aside their schedule for showing, training, foxhunting or breeding, and work with the horse’s ability to recover.  Asking the horse for more than what they can physically deliver sets up a stressful situation.  Failure to take a slow course in rehabilitation may result in a relapse.

Stall or Pasture During Treatment?

The more severe the deficits of your horse, the more important this question becomes.  Evaluate conditions like the seasonal weather, availability of a very quiet buddy for turnout, stress of stall confinement, and the condition of the stall and fencing.  The object of care is first safety of the animal, and second producing the least stress.  Many veterinarians would argue that pasture turnout with a quiet buddy allows the horse to exercise at their level of competence, and avoids the tight turns required in a stall.  Most horses will exercise within their ability to balance, but if they don’t, stall confinement may be necessary. 

As the horse feels better, get creative about ways to slow her down during turnout.  Try placing piles of hay around the paddock, possibly with a treat buried underneath.  Provide toys to investigate, and other horses within sight.

The ugly statistics of EPM say that not all horses will survive.  If the horse goes down and can’t regain its feet, or euthanasia is necessary, a pastured horse is more practical to deal with.

Exercise During EPM Treatment

Realizing how sick your horse is or has been is necessary in decisions about exercise.  If your horse was diagnosed and treated while a neurological grade 1 on the Mayhew Scale, he may be ready for more tasks, sooner than a horse diagnosed at a grade 4.  For the long-term benefit of the horse, take the first rehab steps slowly.

Getting some exercise is beneficial for the digestive tract, circulation, and mental health, but too much may be a step backwards in recovery.  If the horse can walk, start with slow hand walking for a few minutes over level ground.  Take care to make wide turns, as horses with deficits in the hind end have problems negotiating a turn on the haunches. Watch the horse for signs of tiring, stumbling, and attitude.  For some horses, this may be enough to tire them out; others may be ready for more.

Through attitude and actions, the horse will tell you if they are ready to move forward with rehab.  Add minutes of walking, stepping over ground poles, backing, and turns only as the horse feels well enough and can maintain balance.  This initial period of rehabilitation can last a few weeks to several months, and patience on the part of the owner is very important to the horse.  Use the quiet time to build a better relationship with the horse.  The 'Tellington TTeam as a Compliment in the Rehabilitation of Horses with Neurological Deficits' has good exercises for beginning rehab.

During turnout, a trotting horse can effectively compensate for poor balance by the ability to freely place their feet.  It’s common to see the recovering horses playfully canter and buck when turned out.  Seeing the horse moving faster may lead the owner to assume that they are ready for more work.  However, close evaluation with slow, controlled movements may show deficits that are not safe for mounted work.

As the horse feels better, and trots during turnout, the tendency of the owner is to put the horse on a lunge line, or in a round pen.  The process of lunging requires flexibility in turns, balance in carriage, and the ability to use the rear legs in a coordinated manor.  This asks too much of a horse that has balance deficits, or has been out of work for weeks.  Avoid the lunge line and round pen until later in rehabilitation.

Vaccines During Active EPM

Vaccinating a sick horse is never a good idea, because their immune system is already working overtime to fight the infection.  Immunizations will cause heightened activity by neutrophils, a type of white blood cell.  These cells are involved in the process of inflammation – the same process that can cause neurological symptoms in EPM horses.

If your horse is due for vaccines during his treatment for EPM, discuss with your veterinarian which, if any, vaccines can be delayed, and for how long.  The geographic location of your horse, as well as the boarding situation may make delay beyond the end of treatment a risk factor for other diseases.  There is no published protocol for vaccinating the recovering EPM horse.

Ask the vet to prioritize the vaccines you are planning to give.  Consider administering them as single disease vaccines spaced at least four days apart.  The veterinarian may not stock single disease vaccines, so they may have to be ordered.  Some vaccines may come only as a combination, so plan the administration after locating them.  It may be possible for the vet to dispense the vaccines for the owner to inject, to avoid repeated farm calls.

Many owners of EPM horses report temporary worsening of neurological symptoms when vaccines are administered.  This is possible for years after the active EPM has been eliminated.  The anti-inflammatory drug Banamine, and other over-the-counter anti-inflammatory products may help by limiting the action of neutrophils.

Wormers During Active EPM

Any drug given to a sick horse, including wormers, can cause additional stress.  With EPM treatments often running two months, chances are that you will need to worm the horse during or soon after treatment.  There is no published protocol for worming a horse with active EPM.  Perform a fecal egg count to see if you actually need to worm the horse, and what parasite species you should be targeting.  A gut full of worms can also negatively affect the horse’s recovery.

Some owners report temporary worsening of symptoms using the wormer Ivermectin.  It is known to cross the blood-brain barrier, but research has not proven, nor disproved any connection to neurological symptoms.  Use the drug that best treats the parasite species you are trying to kill.

December 2011