Tritrichomonas is an intestinal parasite often responsible for chronic diarrhea in cats.
Unfortunately, the current PCR test for Tritrichomonas is not a be all/end all test. It is expensive and the test results if "negative" are always qualified with the statement that there may not be enough of the protozoa present to produce a positive test. It is periodically a lucky break that we find the organism on fecal smears. We no longer run the PCR test because negative does not necessarily mean negative. Diarrhea is the usual symptom.
St. Louis Cat Clinic will check multiple fecal samples looking for all parasites and pathogenic bacteria. We will trial treat for all usual parasites. If a cat only has male worms, there will never be any worm eggs seen on fecal samples. After we have treated for all of the usual intestinal parasites, we will trial treat for Tritrichomonas for 2 weeks.
Go to the Winn Feline Foundation for more information.