@FjordBCRF, so happy you and Charlie have an answer!! You’ve worked so hard to figure out what’s going on with him.
Preface to the following: I think it’s very reasonable to start with oral minocycline (or even doxy, but mino is much better) and see if you get to where you want to be clinically. With that said: If it were mine, I would (and will, because I’m certain this will happen again) go straight to 10-14 days of IV oxytetracycline with a chronic case.
In one experimental study, i.v. oxytetra-cycline treatment seemed to eliminate persistent infection, while three out of four ponies treated per os with doxycycline showed increasing antibody values by three months after the treatment ended
– from Cornell’s site on Lyme; it links to the actual study, as well as having more information on various treatment protocols,
Here’s why (and I keep meaning to write this up in a bit more rigor, but haven’t had a chance): I bought my mare in 2022, with a history of Lyme. In summer of 2024, she became sufficiently neuro that my vet felt she was unsafe to ride. I did sixty days of mino and still wasn’t happy with how she felt, so I took her to New Bolton neuro in September.
They considered her values negative for Lyme per the spinal tap and we left with a presumptive EDM diagnosis.
Believing that my luck could not possibly be quite that bad, and also just not feeling like she acted like my last EDM horse (having been fortunate (?) enough to have that basis of comparison), I opted to do two weeks of IV oxytet as a Hail Mary after reading the above study plus a couple of case reports of horses that had a history of chronic Lyme, didn’t titer, but resolved with treatment (in humans, not all cases of neurologic Lyme can be identified by CSF testing.) Her tail pull had dramatically improved a week in. Unfortunately, she had done a soft tissue injury as well (likely due to being neuro while running around like an idiot) and so we did six months of stall rest with hand and/or tack walking and then went back to recheck both the soft tissue and the neuro exam.
On recheck neuro exam after the IV oxytet, New Bolton said she was almost entirely normal, and that they didn’t need to see her again unless we had additional problems. They were very surprised by this because she’d been on stall rest, and they said that neuro horses on stall rest usually go downhill quick.
So–again–it’s a pain to do the IV antibiotics and I think it’s very reasonable to try the mino, because it works for a lot of horses. But for me, I’m going straight to the oxytet from here on out, and I thought it might be useful for you to have that in your back pocket either way.
Either way, good luck to both of you! You deserve some of it. You have definitely gotten your Neuro Merit Badge at this point.
This is where doxy is a lot cheaper–can do 1500 for 130 bucks!
Same thing earlier on with Charlie. UGH.
So awesome that you pursued the Lyme diagnosis and treatment and didn’t give up. I have wondered a LOT about neurologic Lyme vs what New Bolton states as fact about it. I am old enough to remember when New Bolton didn’t even believe that Lyme was a problem for horses.