Microbiology Anatomy

Trichomonas vaginalis is a protozoon with variable size and shape. The size varies from 10 to 20 •m. The shape tends to be ellipsoidal in axenic cultures, and amoeboid in vivo. The microorganism has four free anterior flagella and one recurrent flagellum attached to an undulating membrane. The longest flagella is 6-18^m long. The undulating membrane extends for about one-half to two-thirds of the length of the cell. The organism is very mobile, and moves with jerky movements by the flagella and the undulating membrane. At the posterior end, a slender spike projects for a distance corresponding to less than one-third to over one-half the cell length. This spike is the prolongation of an organelle that runs axially through the body - the axostyle. Mitochondria are lacking in trichomonads. Relatively large, dense granules called hydrogenosomes are aligned in three rows along the axostyle. These paraxostylar granules are characteristic for trichomonads. Any cell with the shape and size of T. vaginalis, containing the characteristic paraxostylar granules in typical arrangement, can be regarded as belonging to this species (Honigberg and Brugerolle 1989).

Trichomonas vaginalis is often accompanied by other pathogens in the vagina, many of which produce symptoms that are similar to those produced by the protozoae. For example, among pregnant women, T. vaginalis tends to be accompanied by Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urelyticum, Mycoplasma hominis, and Candida species (Pastorek et al. 1996).

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