Feline Tritrichomonas Foetus Infection

Tritrichomonas foetus infection is a common cause of chronic large-bowel diarrhea in cats, particularly young animals and those in high-density settings such as shelters and catteries. The protozoan colonizes the cecum and colon, causing intermittent, foul-smelling diarrhea often containing mucus or blood that may persist for years. Transmission occurs via the fecal–oral route, commonly through shared litter boxes, and asymptomatic cats can serve as reservoirs.

Diagnosis relies on direct fecal examination, culture, or PCR testing, with PCR considered the most sensitive and specific method. Trophozoites are fragile and susceptible to routine disinfectants, making environmental hygiene important. No treatments are FDA-approved in the United States; however, ronidazole is the recommended therapy, despite inconsistent availability, variable response rates, and emerging drug resistance. Temporary improvement followed by relapse is common, and some treated cats remain infected. Careful diagnosis, infection control, and post-treatment testing are essential for managing feline trichomonosis.