Tritrichomonas foetus as a cause of diarrhoea in three cats

Tritrichomonas foetus as a cause of diarrhoea in three cats Trichomonas-induced diarrhoea in cats has only rarely been encountered in Germany. Three indoor cats from different households were presented separately suffering from severe chronic diarrhoea refractory to treatment and associated with weight loss. Trichomonad protozoa were demonstrated in direct faecal smears and in one cat in intestinal biopsies. The organism was identified morphologically as Tritrichomonas foetus. PCR analysis of parasitic DNA extracted from the cats' faecal samples demonstrated the presence of Trichomonas DNA, though DNA specific for T foetus could not be amplified. Sequencing after PCR amplification, however, resulted in 100 % identity with T. foetus. All attempts to cultivate the organisms on commercially available media failed. Alternative causes of diarrhoea were not detected. The histopathology of one cat revealed trichomonad protozoa and eosinophilic enterocolitis in small and large intestinal biopsies. All three cats were treated successfully with ronidazole and a remission of symptoms occurred after only a few days.