Trichomonas tenax

Trichomonas tenax, or oral trichomonas, is a species of Trichomonas commonly found in the oral cavity of humans, dogs and cats. Routine hygiene is generally not sufficient to eliminate the parasite, hence its Latin name, meaning 'tenacious'. The parasite is frequently encountered in periodontal infections, affecting more than 50% of the population in some areas, but it is usually considered insignificant. T. tenax is generally not found on the gums of healthy patients. It is known to play a pathogenic role in necrotizing ulcerative gingivitis and necrotizing ulcerative periodontitis, worsening preexisting periodontal disease. This parasite is also implicated in some chronic lung diseases; in such cases, removal of the parasite is sufficient to allow recovery (Mussaev 1976). During the early 1900s, prisoners at the San Quentin prison in California were subject to advanced periodontal disease at a rate of almost 90%, owing at least in part to a high rate of infection by T. tenax. In the Journal of the American Dental Association, it was speculated that this high rate of transmission was attributable to the crowding and poor diets faced by inmates. Age is also an important factor (Kofoid and al.1929) and intense inflammation is characteristic. This was one of the very first clinical studies of T. tenax. T. tenax is a commensal of the human oral cavity, found particularly in the patients with poor oral hygiene and advanced periodontal disease. Transmission is through saliva, droplet spray, and kissing or use of contaminated dishes or drinking water. (11,15) T. tenax alone is not known to cause any symptoms. There are merely implications that this parasite may worsen preexisting periodontal disease and in rare cases has been reported to cause bronchopulmonary infections, mainly in patients with underlying cancers or other lung diseases.(4,6,9,11,13,15-17) The organism is believed to enter the respiratory tract by aspiration from the oropharynx. T. tenax trophozoites survive in the body as mouth scavengers that feed primarily on local microorganisms located between the teeth, tonsillar crypts, pyorrheal pockets, and the gingival margin around the gums. T. tenax trophozoites multiply by longitudinal binary fission. These trophozoites are unable to survive the digestive process. The specimen of choice for diagnosing Trichomonas tenax trophozoite is mouth scrapings. Microscopic examination of tonsillar crypts and pyorrheal pockets of patients suffering from T. tenax infections often yields the typical trophozoites. Tartar between the teeth and the gingival margin of the gums are the primary areas of the mouth that may also potentially harbor this organism. T. tenax may also be cultured onto appropriate media. Regardless of patient’s demographic characteristics, it seems that oral hygiene instructions in combination with scaling and root planning can help with controlling excessive colonization of parasites, particularly E. gingivalis and T. tenax and their probable opportunistic infestation. T. tenax can easily be detected through the use of phase contrast microscopy. Biofilm harvested from infested areas of the periodontal pockets can be mounted onto a slide; T. tenax, if present, will be clearly visible. The preparation must use the patient's saliva as the medium, as the use of running water or saline could cause warping. Of the three parasites in the genus Trichomonas, T. tenax is the smallest, measuring only 5-14 µm long and 6-9 µm wide; specimens can be identified by their long axostyles and tails, 4 anterior flagella, and by the recurrent flagellum that raises an undulating membrane which is two thirds the length of the body. This undulating membrane may appear like small legs. It may occasionally appear larger, allowing it to be confused with Trichomonas vaginalis due to similar morphology. In such cases, the presence of an oral or vaginal parasite should be confirmed, due to the ease with which the parasite can be transmitted through direct contact of mucous membranes.