It is a very resistant protozoan. Typically Ronidazole is the drug of choice. It is (flagyl) Metronidazole's big brother. As it does cross the blood brain barrier, some cats will have neurologic signs which will go away with a decrease or cessation of the medication.
Here is an excerpt from a client education on Tritrichomonas. It is written by Wendy C. Brooks, DVM, DipABVP
"How do Cats get Infected?
T. foetus organisms are shed in the feces of an infected cat. Most commonly, transmission occurs when cats share a litter box as the organism can live up to 3 days in fecal material. Any time a cat steps in the feces of an infected cat, organisms can be transferred to the paws and later licked up during grooming.
In the past, several different antibiotics have been reported to be effective but it turns out that this is probably an overestimate since 88% of cats will resolve their diarrhea spontaneously within 2 years. They will still be infected, or at least 57% of them will be, but they will have normal stool and they may relapse with stress.
One treatment option is to simply wait for resolution if the household does not have a large number of cats and the diarrhea is not excessive.
The only drug that is felt to be reliable against T. foetus is ronidazole, and its use is far from straight-forward. Here is what to know:
Ronidazole must be compounded to get a dose in a suitable size for cats.
Ronidazole is not licensed for use in cats; it is a poultry antibiotic. It also tastes really bad and should be provided in capsules rather than as an oral liquid to avoid the taste.
People must wear gloves when handling ronidazole.
The most common side effect in cats is neurotoxicity, which means it is not appropriate to use ronidazole as a trial to see if a cat with colitis improves on it. Ronidazole should be used only in confirmed Tritrichomonas patients.
Neurotoxicity manifests as loss of appetite, incoordination, and possibly seizures. Some experts recommend engaging the cat in play on a daily basis to assess muscular coordination and agility.
Cats being treated should be isolated from other cats in the home to prevent reinfection.
It is not possible to fully confirm that an infection has been eradicated as a negative PCR test does not rule out infection. Experts recommend a PCR test in 1 to 2 weeks after treatment and again 20 weeks after treatment as the closest we can come to confirming eradication.
Ronidazole is usually given once daily for 2 weeks. The diarrhea should be resolved by the end of this course."
Christopher A. Lee, D.V.M., C.V.L.S.
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Last edited by Dr Lee; May 22nd, 2010 at 05:27 PM.