The demon worm has graduated from tritrichomonas prison!
After almost a year of various treatments he is free! We even tested our other cat to make double super sure we banished it from our home once and for all. The vet is hopeful now that that’s resolved, and his other gut issue (c perfringens, which he likely got from improperly prepared food - raw supermarket chicken that he was fed at his previous home) that his tummy troubles should resolve in the next year or so.
If we are very lucky, he may not have IBS at all. His internal med specialist wants to wait a bit and observe before doing something invasive like an upper/lower endoscopy and biopsy.
Now our only problem with him no longer being a quaranturd is keeping him out of the other cat’s food, and having to remind our chow puppy that he can’t be played with like he does with smaller dogs 😬😅