Tritrichomonas Foetus Hits Italian Shelter Cats Causes Chronic Diarrhea

A recent study has identified Tritrichomonas foetus infection as the primary cause of persistent large bowel diarrhea in cats at an Italian shelter, challenging previous assumptions that this parasite primarily affects kittens. The research found adult cats faced equally high infection risks.

In May 2006, a cat shelter in Arezzo, Tuscany admitted 105 cats, predominantly strays with some owner surrenders. Following standard protocols, new arrivals received comprehensive health checks including FIV/FeLV testing, deworming, vaccinations, microchipping, and spaying/neutering. After 21-day quarantine, cats joined communal outdoor areas with shared litter boxes.

Within months, 74 cats developed persistent diarrhea unresponsive to conventional treatments. Initial tests ruled out common parasites like giardia and cryptosporidium. Further investigation revealed an unexpected pathogen.

Researchers employed three diagnostic approaches: direct fecal smear microscopy (n=20), T. foetus-specific culture (n=74), and PCR confirmation (n=1). Results showed 32% infection prevalence (24 cats), with culture detecting significantly more cases (32%) than microscopy (5%).

Notably, 67% of infected cats were adults (18 months to 7 years), contradicting prior beliefs about age susceptibility. All affected cats were neutered domestic shorthairs with no breed predisposition.

Infected cats exhibited varying symptoms from asymptomatic cases to chronic diarrhea featuring foul-smelling, bloody stools with mucus. While most maintained normal activity levels, two kittens developed fatal sepsis-like conditions.

Previously considered primarily an American pathogen, the study confirms T. foetus' global presence with documented cases in the UK (20% of diarrheic cats), Germany, Spain, and now Italy.

Ronidazole (30mg/kg twice daily for 14 days) successfully alleviated clinical symptoms in treated cats, with follow-up cultures showing negative results. However, PCR detected persistent infection in one treated cat, suggesting possible carrier states despite symptom resolution.

Treatment limitations include the drug's unlicensed status for felines and potential neurological side effects. The study notes occasional loose stools persist in some cats post-treatment, though severity and frequency have markedly decreased.

The adult cat infection rate (67%) contrasts with previous studies reporting predominantly juvenile cases. Researchers hypothesize this may represent the parasite's initial introduction to a naive population, affecting all age groups equally.

High-density living conditions likely facilitated fecal-oral transmission, though genetic factors couldn't be ruled out. The shelter environment's role as an infection amplifier warrants further investigation.

Financial constraints limited comprehensive testing, potentially underestimating true infection rates. Diagnostic sensitivity varied significantly - PCR (94%) outperformed culture (56%) and microscopy (14%). Intermittent parasite shedding and single-sample testing may have further reduced detection rates.

The study highlights T. foetus as an important differential diagnosis for persistent feline diarrhea, particularly in multi-cat environments. Researchers emphasize the need for improved diagnostic protocols and treatment options for this emerging global feline health concern.