Tritrichomonas foetus is a protozoon belonging to the order Trichomonadida. The trophozoite is characterised by three anterior flagella and one posterior flagellum. However, similar to Giardia, these are only microscopically visible in fresh faecal samples.
Transmission between cats occurs by faecal-oral route. Transmission between cattle or pig to cat is not documented. Affected animals show typical large intestinal diarrhoea with frequent defaecation in small portions; admixtures of mucus and blood may occur. Tenesmus and uncontrolled defaecation are frequently observed. The general condition usually remains unaffected,
increases in temperature are rare. T. foetus should always be considered as differential diagnosis in cats suffering from chronic, intermittent diarrhoea.
In cattle, Tritrichomonas foetus causes bovine trichomoniasis, which is characterised by inflammation of the reproductive tract in cows leading to repeat breeding and abortion. Bulls transmit the disease but display no clinical signs. In Germany, bovine trichomoniasis is notifiable upon suspicion.