My Horse Has EPM. Why did it take four months to get this diagnosis?

It had been my lifelong dream to have a horse of my own. At 59, my dream came true when I adopted Dance With Joy, an unraced Thoroughbred filly. Last year, I bought a second horse, Ferdinand, through my trainer, because Joy's many lameness issues often leave her un-ridable. I wanted a horse I could enjoy, lesson with and compete. While I am very grateful to have two, lovely, fun, beautiful horses, I have also been extremely unlucky because both have had numerous, serious issues.

While Joy was off work and resting for most of 2019, Ferdinand's own issues began in September when he got a bad abscess. He was lame for almost two weeks. Gradually, Ferdinand recovered and was sound for a few weeks, just before things gradually got bad and weird. He developed what seemed to be a traveling lameness, sometimes in front, sometimes behind, sometimes right, sometimes left. In November, his hind end seemed to give out, and riding him at the trot felt as though he had two flat tires behind. He was worse in our sand arena than on grass, and he tended to stumble behind quite a bit.

Ferdinand was seen by three experienced riding instructors, two chiropractors, a professional saddle fitter, our podiatrist farrier, two magna wave technicians, and two highly recommended local veterinarians. Still, it took more than four months to obtain a definite diagnosis for him.

On February 1st, 2020, Ferdinand was diagnosed with EPM after a third vet performed a spinal tap.

EPM stands for Equine Protozoal Myeloencephaliti. Most folks reading this article will know that many horses in the USA are exposed to the protozoa that cause the illness-from the feces of the opossum-but that most do not get sick. Those that do are thought to have compromised immune systems. Blood tests for EPM can produce false results, in our case, a negative result. Ferdinand was negative for Lyme's as well. Additionally, symptoms of EPM can mimic those of other illnesses. This makes EPM tricky to diagnose.

After Ferdinand's blood tests came back negative but his clinical symptoms persisted, his primary vet suggested that we perform a spinal tap to obtain definitive results before performing other expensive tests on his hind end. This involved a trip to the clinic, an invasive procedure and a bill for $731. However, it was well worth the trouble and cost to finally know what was wrong with him.

Some people who have had experience with EPM do not bother to test for it, but simply treat it and look for improvement. Dr. Sam Crosby, an Oklahoma vet with vast EPM experience, is one who has stopped performing blood tests because of the many false negatives. He believes that new strains of EPM are not detectible in blood serum and opts for spinal taps if possible. A trainer on FaceBook posted a video of her personal EPM body check that she uses to diagnose and then treat horses that come into her barn. Other videos can point owners towards things to check when trying to determine if a horse may have EPM.

Since Ferdinand's diagnosis, I have been reading everything I can about EPM. The science is very complex and there are many possible treatments and many possible outcomes for afflicted horses. One source of information I came across is an EPM FaceBook group. In reading multiple posts, I observed two things. First, many horse owners are extremely observant and notice even the tiniest changes in their horses' behaviors. Second, people were posting similar symptoms and behaviors. It occurred to me that if we sorted and categorized the behaviors we owners were seeing or had seen, that perhaps we could help others who might be in the midst of trying to identify a horse's particular illness get pointed in the direction of an EPM diagnosis. This is important because early diagnoses give horses the best chance for recovery.

Here is a list some of the symptoms and behaviors that I gathered from responses to my non-scientific survey ( a post on the FB group) of owners and trainers who have horses with EPM:

HIND END
Tail:
· weak, wishy, tail muscle
· tail cocked to one side
· absence of tail swishing
Standing:
· standing with one hind leg up or crossed while eating
· resting a back leg
· unable to hold up a hind foot for long
· struggling to stand for the farrier
· parking out in cross ties
· difficulty standing squarely
· leaning on a vehicle for support

FRONT END:
· jerking front legs while being shod
· dropping a shoulder while a foot is lifted
· front legs buckling during sleep
· tripping up front

MOVING:
· balking leaving stall
· a lack of confidence walking
· feeling sluggish, weak, disconnected behind
· moving rear end stiffly
· lack of push from behind
· dragging a toe
· stumbling and falling out behind
· intermittent stumbling
· weak, sore stifles
· changes in movement
· short stridedness
· inconsistency in movement
· 'behind the leg' when ridden
· head tossing
· high head

BEHAVIORS:
· running fence line
· acting naughty for the farrier
· kicking stall walls
· pulling back from trailer
· acting aggressively
· acting grumpy
· seeming miserable
· seeming 'checked out'
· spooking
· lethargy
· depression
· lack of frolicking in the field
· increased reactivity to sounds
· intolerance for fly spray

OTHER OBSERVATIONS:
· sore back
· muscle atrophy
· abnormal sweating
· jaw stretching before eating grain
· lifting a leg while eating
· dropping grain
· increased need for dental floating
· molar tilting
· intolerance for mane being pulled
· muscle wasting, asymmetrically
· weight loss
· colic post vaccinations
· anxiety at girthing; sinking withers
· absence of fly twitching
· curly fur

TIMING:
· Have you recently wormed your horse?
· Have you recently vaccinated your horse?

In addition, Dr. Sam Crosby, mentions horses in his practice who presented with:
· inability to hold chiropractic adjustments, for example, needing 6 treatments in 2 months
· frequent bouts of colic

Dr. Crosby understands that many owners cannot afford to have spinal taps performed on horses to diagnose EPM and has developed his own test, which includes four acupuncture points. I'd love to know what that test is!

The above list of observations and behaviors can be seen on horses with other illnesses as well as in perfectly healthy horses. What horse doesn't rest one leg? for example. I think the important aspect of the list is to think about changes in behavior and the possible indication that a horse may have EPM. It is important to obtain a diagnosis because if left untreated, the horse's condition significantly worsens. EPM is treatable and horses fair best if the disease is caught early.

Had I known that Ferdinand's lethargy + his being behind my leg + his weak tail + his curly fur + his apparent depression + the lack frolic in the field + his sudden and worsening lameness behind + his stumbling behind + his head tossing + his high head in the bridle + his back pain + his lifting a leg while eating + his recent vaccination/boosters could all have been indications of EPM, I could have requested that Ferdinand be tested months ago. But, I didn't know.

So, that is why I have written this article. I hope it may help another horse owner with a puzzle of symptoms as mine, and many horses have had.

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