Tritrichomonas fetus is a protozoan parasite that has been reported in cats since 1956. Infection with this parasite causes chronic diarrhoea accompanied by large bowel inflammation and faecal incontinence. The faeces may be haemorrhagic and/ or mucoid and may be accompanied by flatulence and tenesmus. Little is known as to how infection occurs. It is not known if the bacteria and other flora of the intestinal tract contribute to the ability of the T. fetus to establish and maintain infection in the intestine. It is possible that there are breed susceptibilities to infection. Concurrent infection such as immunosuppression with retroviral (FIV, FeLV) infections may predispose to infection. Most infections resolve spontaneously, but this can take years and relapses can occur. Treatment of symptomatic cats is usually recommended due to the long carrier status and potential to infect other cats during this period. Treatment with Ronidazole, 30 mg/kg, dietary and environmental management are recommended. Metronidazole is not effective and tinidazole has only partial efficacy.
Infection with T. fetus should be considered in cases where there is chronic diarrhoea, and other examinations for bacteria, nematodes, giardia and cryptosporidium are negative. Diagnosis in the past was based upon the observation of the live organism in a direct smear or cultured sample. The PCR test has the advantage of not requiring viable organisms, so transport temperatures are not critical. The PCR is very specific and has a higher sensitivity than microscopy or culture. PCR can detect viable and non-viable organisms, so a positive PCR in a cat without diarrhoea may not indicate the need for therapy.
Approximately 50 grams of litter-free faeces
Passed faeces or collected per rectum. As antibiotics can temporarily reduce faecal shedding, they should be withheld for around seven days prior to testing.