First report of Tritrichomonas foetus in cats from Northeastern Brazil.

Tritrichomonas foetus is a protozoan parasite implicated in intestinal infections in domestic cats, frequently associated with chronic diarrhea. Although reported on nearly all continents, its occurrence in Brazil is rare and has been restricted to the Southeast region so far. This study reports, for the first time, T. foetus infection in two Maine Coon cats originating from the Northeastern region of the country. Both animals exhibited persistent diarrhea unresponsive to initial therapeutic interventions and underwent clinical and laboratory evaluation. Fecal analysis performed on samples obtained by colonic lavage revealed motile trophozoites exhibiting morphological features consistent with T. foetus. Molecular confirmation was achieved through PCR amplification and subsequent sequencing, with sequences deposited under accession numbers PV857727 and PV857728. BLAST analysis demonstrated 100% nucleotide identity with reference sequences available in GenBank. Following diagnosis, both cats received appropriate treatment with Tinidazole (Drogavet, Brazil) at a dose of 30 mg/kg, administered every 24 h for 14 days, resulting in complete clinical remission and subsequent negative fecal examinations. These findings expand current knowledge on the geographical distribution of feline trichomonosis in Brazil, highlight the diagnostic challenges of T. foetus infection, and reinforce the importance of including this protozoan in the differential diagnosis of feline enteropathies.