He's not really ill...but has had diarrhea for several days. I'll take a sample in tomorrow.
It might be a simple bug, or he has been getting into Oscar's CD food and it's a bit rich for him.
I gave him a washing off this morning - he was such a good boy. I use some hair conditioner or fabric softener in a few inches of warm water in my bathroom sink and a small rag. The softener makes the fur in that sensitive area much easier to comb out and get extra stuff.
Will update when I know more.