Tritrichomonas fetus (TF) is a parasite common in cattle, resembling Giardia, which can lead to reproductive problems (infertility, abortion). Although the parasite has been shown to occur in cats since 1996, it has hardly been tested for its presence. TF occurs in both breed and domestic cats, especially where several cats live together.
In a study conducted in the U.S., TF was found in 31% of the animals in their feces. Three-quarters of the cats were under one year old. TF is a single-cell protozoan that thrives in the warm, moist intestinal tract (colon) of the cat. Under a microscope, it looks very similar to Giardia, so it is wrongly often mistaken for Giardia. To demonstrate TF, a specific TF test (culture or PCR) has to be done. However, Giardia is more contagious than TF because Giardia can produce protective cysts. TF cannot do that and therefore, cannot survive outside the body, except in moist stools.
Contamination seems to be mainly via the litter box. Infected cats do not have to show any symptoms. Typical TF symptom is colitis (colon diarrhea), often in the form of a small cowpat, with or without mucus and/or blood, which spreads a very rotten smell. So bad that you want to open all the windows and preferably turn a block yourself. In more severe cases, the anus can become inflamed, and ‘incontinence’ may occur, causing stools to drip out of the anus. For the rest, the infection doesn’t seem to have any effect on the health and coat condition of the cat.
TF does not react to any conventional treatment (such as Metronidazole, Fenbendazole, Amoxicillin, Doxycyclin, etc.). Tests with non-registered Ronidazole seem to give good results (dosage: 30 mg/kg 2 x daily). However, the product may have serious side effects, so it should only be given to positively tested cats. These should be closely monitored during treatment. Research shows that, especially in males, the treatment of the infection is less effective. A possible cause is that the TF infection is also in the reproductive tract of the cats.