We got a new cat—a quite kittenish orange tabby, whom we have dubbed Guillermo, nickname Gizmo.
He is a rescue cat, and the people we adopted him from were upfront with us that he had had giardiasis—an infection by a parasite called giardia. It causes gas and foul-smelling very soft stools.
They held him until the vet they worked with tested him and pronounced him giardia-free, and then they released him to us. But now he has gas and foul-smelling very soft stools, so probably he has re-infected himself.
The thing that makes that possible is that giardia has two life stages. In the first, it resides in the intestine and causes the aforementioned symptoms. In this stage, it is vulnerable to antibiotics. After that, it passes to the second stage, in which it encysts itself. After encysted, it no longer causes symptoms, but neither is it vulnerable to antibiotics.
The problem is, the encysted parasites pass in the stool, the cat cleans itself in its customary fashion, and any encysted giardia get into the gut, where the stomach acids dissolve the cysts, and presto! the animal is infected again! (And apparently, it takes very few re-ingested cysts for a successful re-infection.)
Methods for definitively eliminating giardia are apparently laborious. Advice includes frequently disinfecting every place that the cat might sleep with a bleach solution, and immediately after every bowel movement, thoroughly bathing the cat and completely emptying and sanitizing the litter box. All the while dosing the cat with strong antibiotics, which have their own side effects and are apparently extremely foul-tasting to the animal, so require forcible administration. Some sites actually suggest that you just treat the symptoms and accept that your cat will always have giardiasis.
Anyway, we will be following this up with our own vet very soon and will obviously take their advice, so I’m just asking for now: has anyone had a pet with giardiasis, and what were your experiences dealing with it?