Abstract

Under the scanning electron microscope, the body surface of trichomonads appears ruffled and creased, with numerous crater-like depressions, which should probably be interpreted as the initial stage in the formation of digestive vacuoles or pinocytotic vesicles. Having contacted epithelial cells, trichomonads engulf them totally or partially. Various micro-organisms also become a prey of the protozoon. The different stages of phagocytosis are illustrated in electron micrographs. Gonococci have been discovered in phagosomes of T. vaginalis. Usually their phagocytosis is not brought to completion and they survive within the trichomonads (endocytobiosis). This suggests that the agent of gonorrhoea may be maintained within trichomonads in cases of mixed infection. In addition to morphological details described earlier, T. vaginalis has lattice-like and lamellar structures of uncertain function. Spherical forms are found usually in an unfavourable environment or as a result of budding.