Fall vax includes rabies but otherwise spring and fall vax are the same. And yes, he was on Decoquinate powder from Feb-June this year and we did not see a flare early in the year. He went downhill in Oct. when he switched from night turnout to day turnout and then got hit with Vetera Gold. I now strongly believe he was getting re-exposed to protozoa deposited by opossums in his pasture at night, and his immune system couldn’t fight the EPM infection and deal with the vax also.
My experience was with Lyme disease, not EPM . After being treated for Lyme disease Music developed moderate musculo-skeletal problems for 3 years, starting in October, and going away in May. Each time we thought it was “fixed”, but then it came back in October.
It didn’t seem to matter what we treated her with (and we tried bunch of different things, and a bunch of different tests). The primary symptoms were inability/unwillingness to canter, and unwillingness to trot except in VERY strung out frame.
After the third year, I commented to the vet that it seemed to be tied to to time of year, and asked if it could be tied to day length. He said there was nothing “in the literature” about day length affecting anything musculo-skeletal, but it was cheap and easy to try keeping her under lights (to extend the apparent day length) , and couldn’t hurt.
That fixed the problem completely.
In hindsight, he said that day length IS known to affect the immune system, and he conjectured that there was a residual “supply” of Lyme , and that in summer, when her immune system was strong, her immune system kept it in check. But in winter, with the shorter days, the immune system couldn’t control it.
Again, nothing in the literature specifically. But EPM and Lyme are similar in that you never get completely rid of the bacteria/protozoa, and depend on the immune system to keep it in check.
That started in 1996, and this is the first winter I have not kept her under lights. At 33 I suspect the chance to move around at night is more beneficial than the lights, especially since she is not being ridden.
Just something to try if none of the more conventional approaches are working.
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I can certainly see how that happens as UV light triggers production of Vitamin D and blue light triggers production of T-cells. My horse is outside for roughly 12 hours in the summer, but most of that is at night, so he gets at best maybe 2 hours of sunlight in the evening and 1 hour in the early AM. He actually gets a bit more exposure to direct sunlight in the winter, when he is outside for roughly 4-5 hours in the morning. And that makes me wonder if UV and blue light waves from sunlight are less intense in the morning hours as opposed to early evening. More points to ponder!
