Joe,
I agree with Paige completely on ronidazole! This is a drug that needs very exact dosage and has very serious side effects. During my battles with TF in the past I have lost three kittens to this drug. They were older kittens, 16 weeks old, but since they were loosing weight, they were slowly being given a dosage higher than what they should, as the dosage was not adjusted daily to their weight. They also didn't show the typical symptoms assosciated with the drug, so by the time we (my vet and I) figured out what was happening, it was too late. Has your vet talked to you about the dangers of ronidazole? Since savannahs tend to be sensitive to medications, especially the early gen cats, I personally would be VERY sure (have a confirmed test) that this cat has TF BEFORE just deciding to treat with ronidazole. You can do a DNA fecal test that is quite accurate. Any other test for TF is a total waste of time.
Anatole