Am curious what the all-knowing COTH has to say about the prognosis for a horse with EPM and the results with Marquis + Vitamin E.
Horse is in general good health, but was intermittently “off”, didn’t want to extent in canter. No classic neuro symptoms, just intermittently “tripping” with hind legs that had been diagnosed as “lose stifles.” Blood (not CSF) test came back with high numbers for EPM protozoan.
My guy had the same symptoms 3 years ago – just NQR, not neuro but enough that my trainer suggested getting him tested since another horse of hers had the same issues and ended up having bad EPM. Came back positive enough that we treated him. At the time they had just started using loading doses so I gave him one tube of Marquis on the first day and then did regular doses for the course of treatment. After that was done he went on ReBalance for a few months along with KER Nano-e. He recovered just fine, I did end up using a new treatment a couple of years later (cannot remember the name for the life of me… some vet in Florida had created a therapy and there were two sets of pills/powder to use) as his levels were slightly elevated at the time.
Funny that you started this topic as I’m having the vet come down tonight to do another neuro exam and test him, as he’s been stifle-y and weak behind. Hoping for the best…
Any attitude or temperament changes too? Back about 13 years ago one of our horses was “off” and diagnosed with EPM using the blood test. Vet said treat him with the Marquis and we should see attitude change in a week if it was going to work. No work, no stress for horse during month of treatment.
It was true, horse was mentally much improved in a week, like his old self again!
Horse came back with no permanent damage after the full 28 day course of Marquis. DD rode and worked him after, got his strength and responses all back working well again. He was 100% recovered, went back to work. He was used regularly and often, worked hard for years after with no further EPM issues.
We did a textbook treatment, exactly as called for in package directions. No loading doses, no extra other vitamins or treatments mentioned in the many posts about EPM on COTH. No extra courses of Marquis later, they were not needed.
He was diagnosed very early, treated early with full recovery. Vet said watching horse go he never would have picked him for having EPM. We family members got together to dicuss horse “acting peculiar”, which is when Vet came and found nothing. Smart old Vet listened to me and drew blood to test so EPM could be crossed off the list of ‘maybe’ problems. We were all surprised that horse really had it!
I was very happy with the Marquis results on our horse. I would use it again and recommend Marquis to my friends. It did what it was supposed to do. We did not try “improving it” with additional additive items or by changing dosages manufacturer put on the packaging. Kind of like baking, not following directions, yet still expecting the same perfect results!
We cross tied horse in the aisle, gave his dose each morning. We gave a snack so he swallowed meds, left him stand there about 15 minutes to know he swallowed all the dose. Couple times he dropped the meds on the floor while we were not beside him. Meds were easily seen to get back in his mouth and see him swallow it then. Meds won’t work if he does not swallow the whole daily dose.
Good luck with your horse and treatment. You might use the California Davis test for EPM if you get him rechecked later. Newer test, fairly inexpensive, tells more than the plain blood test will. Recommended by many here on COTH.
We recently did the SAG blood testing, then Orogin then Neuroquel, recommended by the Florida people. It was quick,inexpensive and easy. My horse gobbled down the pills in his grain. He symptoms, which were subtle, have resolved. Hopefully, they will not recur.
My EPM horse also responded well to Marquis … But … She either kept getting re-infected or was harboring a reservoir the Marquis didn’t reach, because she relapsed several times. I had to treat her multiple times, then maintain her on a compounded blend of meds after that.
As others said, a change in attitude was the first indicator something was wrong, followed by ataxia / neuro impairments.
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Not my horse, but a friend’s - horse was diagnosed with EPM and treated with a course of Marquis. Same as your horse, not lame, just NQR. Problems backing up, some issues in canter, and energy issues. And muscle loss. Went through quite a few diagnostics before they tested for EPM - it just isn’t that common here. That was last year. Horse is back at work this year, and showing 2nd level with great scores. She still struggles with backing up, but otherwise, all is well - she’ll be doing 3rd level next year! Changes are not an issue, just the reinback, which may be a permanent thing. She’s scoring low 70s at 2nd level, so I’d call that a pretty good recovery 
And a positive experience with Marquis…
Doesn’t the blood test only provide you with a number related to antibodies? I’ve read that 50% of horses will test positive for the antibodies in endemic areas. I’ve also read that the only way to get a truly definitive result is at necropsy…
Does anyone know the percentage of horses that test positive for antibodies ALSO having a positive test of spinal fluid?
I think that the assumption of EPM with every horse that is “off” or “NQR” could be dangerous. There are so many other possible causes of being “NQR” - like my guy with a partially fused hock (and related soreness - tripping).
I’m not suggesting that the OP hasn’t done due diligence, just more of a general question.
Thanks for all the replies. Current statistics show no difference between results from CSF and blood tests.
Since there is a lot of risk with doing a spinal tap, electing to do a course of Marquis in response to blood test results is preferred course. I was just curious what others had experienced.
FYI…There is a new(ish) test called the peptide SAG ELISA. It is run on serum, and looks for the presence of antibodies specific to three protozoal surface antigens…SAG1, 5, and 6. The test will measure 100% of the strains of Sn.
So a very reliable test.
We did not do the spinal on advice of the old Vet. It was $ 475 for a draw, and almost always needed a second draw after contaminating the first one with blood. This had to be done at the State College Vet Clinic. So that cost of $950 to make it positive that “Yes horse DOES have EPM” was wasted money to us.
Cost of Marquis treatment then, was almost the same price as a spinal. Vet said “Better to spend our money treating, than a confirmation of positive blood test for the EPM.” Vet assured us horse would show us if Marquis was helping within a week with a big attitude change for the better. Vet had treated a number of EPM cases, both slow onset like our horse and sudden onset with the horrible nerve damage. Lot of EPM locally, just that the news was not common among owners yet. Vet said stressed horses got it, and horse had his whole routine changed with DD joining horse 4-H. Vet figured most local grazing horses carried EPM, so stress lowered immunity allowing the disease to escape into the body. Most EPM cases found were sudden onset. They were put down within a few hours because they were dangerous to be around, hurting themselves and people.
I learned about EPM here on COTH, no other information around. Many wrote of the variety of peculiar things in their common wrongness in “being off” but not any to point at EPM.
Our horse came back all the way. We caught it early. Even the Vet saw nothing wrong watching horse go. We just knew he was “not himself” from years of owning and using him. The hints mentioned, tripping now and again, not wanting to back up, unwilling to work, not hanging with his herd buddies. Then finally in a turn he pulled a shoe. Horse had always known where his parts were, never pulled a shoe all the many years we had him. Husband, DD and I had a talk, each of us adding odd things we each saw to the list that got kind of long! Husband thought issue was age. At 18yrs horse had wear and tear from years of work in hard use, so we had the Vet check done to learn more. As I said, I had the Vet pull blood to do an EPM test along with Selenium test, a blood panel, more to rule out issues than thinking those were problems. Vet said to wait for test results after not seeing anything wrong in movement. We could do X-rays later.
Also went straight to the Marquis after a positive blood result. The horse was lethargic and “just not quite right,” starting to display neurologic symptoms but not to the extent that they were interfering with his daily life. Marked improvement after a week, full recovery after the month’s treatment done by package directions. The vitamin E is a new one on me, but it makes sense to add.
Another horse I knew, though, was diagnosed late, and by the time the blood test was done, also had Lyme. He was non-responsive to treatment for either disease and ultimately had to be put down as his neurologic symptoms made him a danger to himself and others.
There is no test for EPM that has an accuracy level that would cause me to use it- and this is over 15 years since I first learned of, and started dealing with, the disease.
Here is the short course- if you feel that your horse has it, and that there are enough issues pointing toward it that you want to treat for it, Dyclazuril has the best record.
You need to pick your drug (Ponzuril is a metabolite of the original Bayer drug, Toltrazuril labeled as Baycox) and I have no confidence in Bayer. Used their drugs, and had relapses. Your drug needs to penetrate the blood brain barrier, and actually KILL the protozoans (there are several types that are causative). You need to take your horse to what is called “steady state”, which is the highest amount of the drug that can be sustained in the blood stream, and keep them there for as long as your wallet allows, but, IMHO a minimum of 45 days IF your horse is truly exhibiting gross propriaceptive deficits.
Why? Because no one actually knows the life cycle of the psarcocysts ( I am sure I butchered that spelling) and I personally -as a layperson- believe that they encyst in the cord. So, your drugs need to do two things. 1- Ambush them when they appear, and 2- allow the horses immune system to reboot such that it can deal with them next wave.
Along the way, you need 10K units of high quality vitamin E per day, to help support the nervous system, and a high quality immune booster, amongst other good things.
Best of luck- it can be a bear to deal with!
“Few (<1%) of exposed horses develop clinical EPM.”
https://ahdc.vet.cornell.edu/docs/Equine_Protozoal_Myeloencephalitis_EPM_Testing.pdf
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