Molecular identification of Trichomonas tenax in the oral environment of domesticated animals in Poland – potential effects of host diversity for human health

Introduction. The protozoan Trichomonas tenax is considered to be a human specific flagellate of the oral cavity, found in humans with poor oral hygiene and advanced periodontal disease. Morphological variability and great similarity between species occurring in humans and animals, complicate the specific identification of trichomonads, using microscopic examination and other standard parasitological techniques. Objective. The aim of the study was to search for and identify T. tenax in domesticated animals using molecular methods. The obtained data were assessed in terms of potential effects of a spread of the species deriving from the animals in the human environment. Materials and method. 301 animals: 142 dogs, 57 cats and 102 horses, were examined in terms of their mouth status and occurrence of trichomonads. ITS1–5.8S rRNA-ITS2 region was amplified and sequenced. Results. Finally, 7 dogs, 3 cats and 1 horse were diagnosed positive for T. tenax by PCR. In the oral cavity of 9 /11 animals, gingivitis and dental plaque accumulation were diagnosed. 9 /11 sequences of trichomonad isolates showed 100% identity with T. tenax sequence derived from the GenBank. The sequences of 2 isolates differed by substitutions. Conclusions. It was proved that T. tenax, considered so far as a human specific parasite, can also inhabit the oral cavity of dog, cat and horse. To summarize, T. tenax was detected in the mouths of different domesticated animals, indicating that in Poland it can colonize a wider range of hosts than previously known. The owners of 3 dogs showed oral tissue inflammation of different intensity and were also positive for T. tenax; therefore, oral trichomonosis spread from humans to domestic animals and conversely should be taken into consideration.