Wow, that was fast. Thanks, folks. I knew I'd come to the right place for advice. Good ol' Mudcat!!!

Neither kitty gets milk. Water, dry food and canned food only. The adult cat gets dry food for adults, the kitten gets dry food for kittens. I was giving the kitten canned food for kittens, but I ran out and have been giving him canned food for adults lately... could the problem be that simple??? (Switching back to kitten food TODAY!)

Hmmm, probiotics, you say? Cooked rice? Scrambled egg? (Funny, egg has quite the opposite effect on me... *grin*)

As for worms, the vet had tested a stool sample at 5 weeks and had found nothing to indicate roundworm. Roo had been wormed before I got him, but my vet gave him 2 oral liquid treatments anyway to be sure. The tapeworm could not be diagnosed on the test, but they sure showed up on Roo's butt; vet gave him a pill for tapeworm and I have seen none since. Ear mites were pronounced "gone" upon examination last Friday; 5 weeks of treatment with drops (in both cats!) did the trick.

I'd kept the cats isolated from one another until last Friday when Roo was inoculated, tested negative for FeLV and the other standard nasties, and pronounced healthy. When I was told by the pro that the cats could mix, I opened the door. So they've only been having limited contact (not 24 hours a day), mostly visual-contact-only, since Friday. The diarrhea started before that, and Roo has been bony all along.

Roo gets cuddled and fussed over as often as he'll let me hold him still that long! He does take catnaps on me quite often.

Another vet, eh? That would be the third one, then, since the first vet Rupert saw was the one who had treated him at the shelter. The shelter vet was the one who pronounced Roo parasite-free when he most definitely was NOT. My vet was visibly pissed, and said it was "inexcusable" of the shelter to give me a cat with ear mites. He's been my vet since 1987, and my kitties have lived long lives under his care, and he doesn't seem concerned about this kitty's current appearance, so I'm willing to hang in with him for the time being...

...but perhaps it's time to bug him again and see if he has further advice for me.... I'll mention the ideas listed here. Please keep 'em coming!

Thanks again!
Sharon