Persistent EPM

[RideEveryStride]

Has anyone had a horse that consistently struggled with EPM when not on medication? I am unsure if he is relapsing, or if he has had a continuous infection this whole time. Background is:

6 year old TB suddenly became VERY stumbly under saddle at the trot and canter in early May this year. He had also lost some muscle overall, and especially on his topline. Failed a neuro exam and was diagnosed with EPM. No blood test as EPM is very prevalent in our area. He was initially treated with:

• One round of Toltrazuril getting one full tube every three days, did 5 tubes total. Also got two jugs of DMSO with that. The DMSO made him a little colicky for about two hours after administration.
• Did one bottle of compounded Rebalance.
• Did another round of Toltrazuril getting half a tube every other day for 10 days. No DMSO that time.
• Received two bottles of compounded Rebalance.
• Has been getting 10,000 IUs of Vit E daily since diagnosis.

During initial treatment, he progressed slowly but surely (no stumbling) and was eventually back to jumping small courses with no issues in Mid-late July. His body condition bounced back quickly and he has maintained a lovely condition since. All was well until he fell on his face while cantering during a dressage test in early August. No injuries for either of us thank goodness! He has had a consistent mild stumble since then when ridden or lunged. He has not been asked to canter since this incident, but gets around fine in the pasture. Since then we have done:

*x rays of feet, neck, and back
-Hoof x rays were normal but his toes were a bit long. Long toes have been addressed, did not help alleviate tripping issue.
-Back x rays were normal.
-neck x rays showed mild enlarged articular process joints at C6 and C7, but the vet did note that the changes are not dramatic. Recommended a Myelogram as they encourage this any time a horse falls while being ridden.

*We also did another round of Toltrazuril getting a half tube every three days for four doses total.
*Chiro noted he has hyper mobility in his neck, but no other physical issues that might be contributing to the tripping. Recommended lunging with the Pessoa to strengthen him.

Interestingly, the most recent round of Toltrazuril got him to stop tripping for about two weeks. However, after those two weeks his tripping started back up again. He seems to be slowly becoming more neurologic each day currently. His condition is lovely and he acts totally normal personality wise. He has been lunged in the Pessoa regularly recently, but I am starting to back off on this as he seems to be struggling more. Vet pulled blood for an EPM test yesterday and we are hopeful we will have results tomorrow.

The next logical step would be to take the horse to the clinic for additional testing. I have been quoted $5500 for the diagnostics the clinic would like to do. This includes new neck/back x rays, a neuro exam, blood work, epm tests, and a myelogram (I am possibly forgetting additional diagnostics included in that quote). The diagnostics would require a two night stay at the clinic. His has surgical insurance only, so none of the diagnostics would be covered. However, if he would need basket surgery, that would be covered. I am hesitant to schedule him at the clinic as the cost is out of reach at this time, and I am unsure that I would want to put him through a myelogram and potential basket surgery. Forgive me if this is a stupid question, but is there value in doing EPM diagnostics in the clinic versus continuing to try different medications on the farm?

Of course, no next steps will be determined until we get the results from his blood test tomorrow. But I wanted to consult the hive mind for any similar experiences or suggestions in the meantime.

[SusanO]

You can treat for the protozoa and kill them (hopefully) but you can’t always reverse the damage to the spinal cord from the protozoa. That does not explain why he got better for a short time though.

[Ziggy793]

I keep my EPM gelding on twice a week diclazuril and probably always will.

When we was initially diagnosed we did a month of toltrazuril (no change), followed by two months of marquis (ponazuril) and a full month of protazil (diclazuril) and he improved enormously with the diclazuril/ponazuril, but I felt that when he went off the meds there was a bit of a regression. He was never tripping or obviously neuro but presents with hind-end funkiness.

My impression is that totally wiping out the infection is really hard. My assumption with my gelding is that we got the population down to where his immune system can mostly handle it, but still benefits from some additional help keeping things in check.

And then, as @SusanO notes, even if you do manage to wipe the protozoa out, that doesn’t automatically reverse the nerve damage, which takes a lot of time to heal. So another cause of seeming “relapse” when there’s no actual relapse can be something else causing increased inflammation that’s aggravating that existing nerve damage.

[horsepooramateur]

From my research, experience with my own horse, and that of close friends, I firmly believe each horse responds differently to meds and there is no right answer for all. In my personal experience, Protazil has been the gold standard. My suggestion would be a month or two of Protazil if you can find a way to afford it, followed by another month or two of compounded levamisol/decocoquinate (this is a lot easier on your wallet). The recommended protocol from Dr. Liz Johnson, the neurologist at New Bolton, is continued tapered doses of Protazil for maintenance following treatment. I think this completely varies…given what you said about living in an EPM-prevalent area, I’m assuming you may be in the Mid-Atlantic and your vet might be familiar enough to consult with Dr. Johnson. We are very lucky to have her as a resource, she is extremely knowledgeable and dedicated to the treatment of EPM! I’m honestly surprised that your vet recommended the meds they did…I haven’t heard of anyone recommending Rebalance especially in 10 or so years. It’s so much more complicated to administer and similar to birth control in humans, if you don’t get the timing exactly right with food/time of day etc. you are not going to have great luck! Pretty much every vet I know in our area uses Protazil, Marquis, or the compound I mentioned if the other two are out of reach financially. Best of luck with your guy and I’d highly suggest exploring the consultation with your vet/see if she will consult with you directly before dropping $5k on a visit!

[FjordBCRF]

@SusanO

You can treat for the protozoa and kill them (hopefully) but you can’t always reverse the damage to the spinal cord from the protozoa. That does not explain why he got better for a short time though.

My understanding as a newly minted EPM horse owner, none of the meds kill the Protozoa, they stop them from reproducing and spreading further. The idea is then to help the immune system fight them off like it should once the reproduction is halted. In advanced cases, there is medication that can help recovery of polyneuritis.

I recently shared this in a different EPM thread but will share here too as it helped me sort through the options.

1. Protazil (Diclazuril)

• Targets : Sarcocystis neurona by inhibiting the protozoa’s ability to reproduce and spread within the nervous system.
• Safety Profile : Safest option, minimal side effects (rare gastrointestinal upset).
• Cost : Moderately expensive.
• Ease of Administration : Easy—pellet top-dressed on feed.

2. Marquis (Ponazuril)

• Targets : Sarcocystis neurona by disrupting the protozoa’s energy production, which inhibits its reproduction.
• Safety Profile : Generally safe; possible mild gastrointestinal upset or neurological symptoms.
• Cost : Expensive.
• Ease of Administration : Paste form, daily dosing.

3. Rebalance (Sulfadiazine/Pyrimethamine)

• Targets : Sarcocystis neurona and Neospora hughesi by interfering with folic acid metabolism, preventing the protozoa from multiplying.
• Safety Profile : Moderate risk; potential for anemia and gastrointestinal issues, requires blood monitoring.
• Cost : Least expensive.
• Ease of Administration : Oral liquid, requires daily dosing.

4. Levamisole/Decoquinate (Compounded)

• Targets : Sarcocystis neurona by stopping protozoa’s energy production (decoquinate) and boosting the immune response (levamisole).
• Safety Profile : Riskier; immune suppression, gastrointestinal, and neurological side effects.
• Cost : Moderate.
• Ease of Administration : Powder mixed with feed, 10-day course.

[Simkie]

Before thousands in testing, trying a different med is worth a shot. I found this paper a very useful resource when I was in the summer of epm last year (I treated my entire barn…actually more, because I bought a horse, and she was also positive )

Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a...

I had very good results with the compounded ponazuril from FarmVet, and it’s very inexpensive. I dosed it with oil, per this paper:

Effects of coadministration of corn oil and ponazuril on serum and...

Something that isn’t very well circulated but is really worth bringing into the EPM convo is the FDA letter regarding Dr Ellison’s pathogenes work–the decoquinate/levamisole combo. I’ll link that, too:

https://www.fda.gov/files/animal%20%26%20veterinary/published/2017-Untitled-Letter-to-Pathogenes--Inc..pdf

The important part is at the end:

“You appear to be defining a disease by assessing individual case responses to unproven
treatments, then using those responses to unproven treatments to then define the case
population to demonstrate effectiveness.”

This is terrifying–she is using the response to her drug as the defining characteristic of the EPM diagnosis. If they don’t get better, they must not have EPM. And if they do get better, they had EPM and her treatment is so effective! Yikes.

Hers is the only research here, and the FDA considers it insufficient. While there’s a lot of anecdotal report around it, it’s impossible to know how it compares to other drugs that have actually undergone proper research.

[FjordBCRF]

@Simkie

(I treated my entire barn …actually more, because I bought a horse, and she was also positive )

Do you do anything like an annual maintenance dose for your horses? Once we are through the Marquis, unless the vet strongly recommends continuing treatment, I don’t plan to. I would like to stay on top of this though so it doesn’t ever get out of hand knowing that he will probably throw a titer. The ponazuril powder has a much nicer pricetag and I would be absolutely open to doing that at some cadence moving forward.

[Simkie]

@FjordBCRF

Do you do anything like an annual maintenance dose for your horses?

I don’t, although I tested two of them this spring to see where we were, and they both had very low titer values, which was comforting.

Last year when I was neck deep in it all, I did really look around at if I should just treat once a year, and when that should be if so. There’s not a lot of support in treating asymptomatic horses at all, never mind just straight up prophylactic treatment. But it can also be such a subtle disease, and neuro deficit diagnosis is such a subjective thing, so I really struggled with … just what should I be doing?? Because it really seems like once you have obvious “wow that’s neuro” symptoms, you’ve also got the risk of damage that may not be recoverable from, and man, I’d really like to avoid that.

In the end, they’ve been fine, and we’ve had no relapse, and I think I’d be hard pressed to talk my vet into treating without testing or treating wholly “negative” horses, so I’ve left it alone. Truly, I’m not sure if that’s the right answer, but it’s really what the literature supports, so … here we are.

[FjordBCRF]

Boy do I feel all that! Thank you for sharing.

[2tempe]

OP - my sympathies as I’ve been through one of these situations and its a process. Short version - my horse showed moderate changes on xray: C5 - C7. Tested negative for EPM, Lyme and one other thing, I forget. Neuro - relatively mild symptoms included some tripping. Many changes to his overall ability to work - stiffness to one side, lost the ability to do an ok flying change to one side. Lost some of his work desire.
I did the mri/myelogram and that showed a number of things: Some arthitic changes all down the cervial spine, mild closer to poll. It also showed spinal compression and some issue where the the foramen opening was pressing on nerves.
I gave some thought to basket surgery, and there is a thread here about some who are in the rehab process. The surgery is pricy ($15k -ish) but your insurance would cover lots of this. The rehab process is long and labor intensive. Be sure you understand this in advance of decision. Also understand that it may only improve the neuro symptoms a grade or so; there are not a lot of examples of horses being completely better and back to original job. There are stories about repairs needing to be done to the parts they install.
I chose to retire my 10 yr old.
The first thing I would do is verify or rule out EPM as best you can, rather than throwing meds. Test things like Lyme, EDM, etc and stop before the myelogram. See what you find.
I’m not familiar with EPM meds, but I wonder if there is something that what he was getting that calmed inflammation for a while and thus he felt better even if he really didnt have EPM.

[No1]

Lots of horses require some kind of on going treatment. My horse responded to toltrazuril much more than to Protazil and so gets a ‘maintenance’ dose of toltrazuril every other week. She’s also on a decreasing dose of levamisole still.

Rebalance is not widely used anymore and I’m pretty sure decoquenate/levamisole is cheaper.

[sparkygrace]

There are a few other discussions about EPM and I have commented on all of them. My horse was diagnosed over two years ago. He had some problems with his left hind.

I treated him for three months with Protazil. I added Emcelle to his diet. He showed quite an improvement, so I reduced the Protazil to 1/2 dose/ day, then once a week. It was costing big $$$, so I switched to compounded ponazuril twice a week.

My horse shows no signs of EPM. He never lost muscling. Unfortunately, he has some arthritis in his stifles, but that’s an unrelated issue.