Do you trust your vet? And Stress?? Bizarre diagnosis. I'd get a second opinion if I were you, as this has gone on long enough, especially with your history of poisoned animals.
What did they test his poo for? Poison? They may have tested for parasites but not bacterial strains, and if there is a strain of bacteria causing this he needs a lasting anti-biotic to kill it off.
I had a discussion with my vet when similar symptoms were troubling Pursley a few years ago, he said that there was little point testing poo samples where bacterial infection is suspected. Its expensive and you need to have a clue what you're looking for as there are numerous tests for various different things. Administering a single antibiotic injection was a cheap and effective way of establishing whether this is the cause. It turned out to be correct because her tummy was back to normal in within two days.
He did say that if she hadn't improved then testing would be appropriate, but at least the bacterial infection would have been ruled out, so the tests would be simpler.
I'm assuming he's been wormed to rule out parasitic infection?
Sounds like your vet could do with talking to mine.
