Dear Nancy - >I don't write very often but the subject of giardia is one I am >experienced with. I've been a veterinary technician for 22 years and >have found that veterianarians, tecnicians, and even some laboratories >will often misdiagnose Giardia. The yeast (a nutrient) in the food they >eat passes through in their stools and looks similar enough to giardia >cysts that it is mistaken for them. I'm glad you brought this up. I agree wholeheeartedly. While I generally don't want to tell people to ask their vet if they are sure if it is really Giardia, I am generally suspicious whenever I hear the diagnosis. Ferrets do have a lot of yeast in their stool, which is slightly smaller, but can be easily mistaken for Giardia. The big difference to the inexperienced is that while both will move under the scope, Giardia moves in a more directed fashion, due to the presence of flagella, and yeast just tend to roll along on the eddies and currents of the fluid under the scope. I liken yeast to tumbleweeds - they have no ability to move on their own, but they are often in motion due to other factors. Truly, Giardia can be isolated from clinically normal ferrets - I think that it gets blamed for a lot of diarrheas that spontaneous clear up on their own. The problem is that the recovery is often coincident with treatment, so it looks like the treatment is working and the diagnosis of giardiasis sticks. But what am I telling you this for - you've been doing this longer than I have! With kindest regards, Bruce Williams, DVM [Posted in FML issue 3290]