Canine Trichomonas tenax mandibular gland infestation.

Background: Several species of trichomonads are intestinal or urogenital parasites of humans and animals, with only a few species typically being located in the oral cavity. The prevalence of oral trichomoniasis in dogs is approximately 15-25 %, although the prevalence varies among different populations and depends on age, sex and the health of the oral cavity.
Case Presentation: A case of mandibular gland infestation by trichomonads in a 13-year-old female Dachshund with advanced periodontal disease and oral trichomoniasis is reported. The dog was referred due to a history of a painless swelling over the left submandibular region that increased in size over time. Based on physical and ultrasound examinations, a final diagnosis of mandibular gland cyst was established and transcutaneous needle aspiration was carried out. Numerous mobile trophozoites of trichomonads were found by microscopy and culturing for trichomonas was performed. The species was finally characterized as Trichomonas tenax by polymerase chain reaction and sequencing.
Conclusions: Studies have shown that T. tenax can be found in humans in atypical locations such as the salivary glands and upper and lower respiratory tracts. According to our knowledge this is the first report of T. tenax being present in the salivary glands of a dog. Because of the relatively high prevalence of trichomoniasis in dogs with periodontal diseases, these parasites should be considered together with bacterial and viral agents in salivary gland infections, especially in individuals with compromised oral health.