Morphology and Identification
- T. tenax is the smallest species in the genus Trichomonas, measuring 5-14µm long and 6-9µm wide.
- It can be identified by its long axostyles and tails, 4 anterior flagella, and undulating membrane.
- The undulating membrane may appear like small legs.
- It may be confused with Trichomonas vaginalis due to similar morphology.
- Confirmation of an oral or vaginal parasite is necessary in such cases.

Life Cycle and Transmission
- T. tenax trophozoites survive in the oral cavity, feeding on microorganisms between the teeth and gums.
- They multiply by longitudinal binary fission.
- Trophozoites cannot survive the digestive process.
- There are no cysts, and transmission occurs through direct contact of mucous membranes.
- The parasite can be transmitted through saliva, droplet spray, kissing, or contaminated dishes/drinking water.

Clinical Manifestations
- T. tenax is a commensal found in the oral cavity, particularly in individuals with poor oral hygiene and advanced periodontal disease.
- It is not known to cause any symptoms on its own.
- It may worsen preexisting periodontal disease.
- In rare cases, it has been reported to cause bronchopulmonary infections in patients with underlying lung diseases or cancers.
- The parasite can be found among dental calculus and tonsillar crypts in infected hosts.

Diagnosis
- Mouth scrapings are the specimen of choice for diagnosing T. tenax trophozoites.
- Microscopic examination of tonsillar crypts and pyorrheal pockets can yield typical trophozoites.
- Tartar between the teeth and the gingival margin may also harbor the organism.
- T. tenax can be cultured on appropriate media.
- Phase-contrast microscopy using the patient's saliva as the medium is an effective method of detection.

Research Studies
- Trichomonas tenax culture in vitro (Published in 1997, Journal: Journal of Fujian Medical College)
- Neutralizing salivary pH by mouthwashes after an acidic challenge (Published in May 2017, Journal: Journal of Investigative and Clinical Dentistry)
- Molecular identification of Trichomonas tenax in the oral environment of domesticated animals in Poland (Published in September 2018, Journal: Annals of Agricultural and Environmental Medicine)
- Zoonotic Trichomonas tenax and a new trichomonad species, Trichomonas brixi n. sp., from the oral cavities of dogs and cats (Published in April 2017, Journal: International Journal for Parasitology)
- First report of Trichomonas tenax infections in the Philippines (Published in April 2014, Journal: Parasitology International)