Morphological and molecular characterization of a species of Tetratrichomonas present in feces of Brazilian sheep (Ovis aries) and goats (Capra hircus).

The trichomonads form part of the phylum Parabasalia, a complex assemblage of diverse species of flagellated protists, with some members recognized as pathogens of men and/or animals. Associations, probably as commensals, between the species Tetratrichomonas ovis and sheep were reported in North America during the 1960s based on morphological and cultural characteristics. Intriguingly, no subsequent studies of this topic have been published. Feces, collected from sheep (n = 55) and goats (n = 14), reared on small-scale, production facilities in Southeastern Brazil, were examined for parabasalids. Protozoa, demonstrating morphologies and motility characteristic of trichomonads, were detected by direct microscopy in 64% of sheep and 43% of goat samples. In contrast to T. ovis, none of the samples could be cultured in Diamond's medium; however, cultures were obtained for three goat and seventeen sheep samples in peptonized broth. Based on morphological analyses, all isolates were classified as members of the genus Tetratrichomonas. Sequencing of the ITS1-5.8S rRNA gene-ITS2 region revealed three highly similar genotypes that were essentially identical to sequences reported for Tetratrichomonas spp. isolated from the preputial cavity of cattle in the USA and Southern Brazil. The findings of this study extend and enhance our knowledge of parasitism in small ruminants by parabasalids.