Interesting that you had a problem with loose stools, Pat, because I had exactly the same but with a puppy who was eventually discovered to have Giardia. It did take us a very long time though and in the meantime the pup was suffering.
It also happened to a friend of mine herself who for years had a stomach problem that finally was discovered to be a Giardia infection. Because of my experience with the puppy, I had jokingly suggested the problem to her as well.
Yes… Giardia "hides" very well..... Many Vets will write it off to a sensitive digestive system when in fact it is not. Like I said with my OJ, once it was cleared up, he could eat anything...