The most common treatment for Giardia is flagyl (Metronidazole), Panacur is for worms? It can sometimes take more then on treatment of up to 21 days to cure.
Also your foster may be dealing with other health issues. Very well could be IPSID or IBS (Inflammatory Bowel disease). Stress and/or emotional nature can be a factor. You might want to try one of the Wellness foods, Potato and Duck is one that I use…. (no grains)...
Do you know anything about the foster? where she came from? Andthing on her sire and dam?
Yup, Panacur is for worms, but this was lvoss quote from the other thread…the other thread also talked about the same thing happening with Mantis' dog.
"When Nicky was about 18 months old he had Giardia, the vetI had at the time prescribed Flagyl and then it would recur and they would represcribe this happened about 3-4 times, I was frustrated because it wasn't going away. Finally, I tried Panacur which is Fenbendazole. Cleared it up and none of the recurring episodes every 4-6 weeks."
My vet thought Panacur might be a good solution as well, but I never went down that path. In that other thread is also an article from Basenji Companions newsletter that talks about using it for Giardia that is quite interesting.
...not saying that is the problem, but could it be?