|Two T. vaginalis trophozoites. Colorized SEM|
Brugerolle & Lee 2000
Some organisms in this order include:
- Trichomonas vaginalis, an organism living inside the vagina of humans
- Dientamoeba fragilis, parasitic ameboid in humans
- Histomonas meleagridis, parasite that causes blackhead disease in poultry
- Mixotricha paradoxa, a symbiotic organism inside termites, host of endosymbionts
Species in this order typically have four to six flagella at the cell's apical pole, one of which is recurrent - that is, it runs along a surface wave, giving the aspect of an undulating membrane. Like other parabasalids, they typically have an axostyle, a pelta, a costa, and parabasal bodies. In Histomonas only one flagellum and a reduced axostyle are found, and in Dientamoeba, both are absent.
Trichomonads reproduce by a special form of longitudinal fission, leading to large numbers of trophozoites in a relatively short time. Cysts never form, so transmission from one host to another is always based on direct contact between the sites they occupy.Kamaruddin, Mudyawati; Tokoro, Masaharu; Rahman, Md. Moshiur; Arayama, Shunsuke; Hidayati, Anggi P.N.; Syafruddin, Din; Asih, Puji B.S.; Yoshikawa, Hisao; Kawahara, Ei (2014). "Molecular Characterization of Various Trichomonad Species Isolated from Humans and Related Mammals in Indonesia". The Korean Journal of Parasitology. 52 (5): 471–478. doi:10.3347/kjp.2014.52.5.471. PMC 4210728. PMID 25352694.
- PreTest Pharmacology (14 ed.). p. 221.