Trichomonas microti, n. sp. (Protozoa, Mastigophora)

Abstract

T. microti is similar to T. hominis but is smaller and more rotund, and has 4 anterior free flagella in contrast to the usual 5 in T. hominis. The undulating membrane has a somewhat thicker double marginal filament which follows a more sharply spiral course in comparison with T. hominis, and often does not reach the posterior end of the body. There is a posterior free flagellum. The costa is like that of T. hominis but appears thicker in protargol preparations. The parabasal apparatus consists of a filament which may be Y-shaped, attached to the blepharoplast accompanied by a small round body near its mid region. A pelta, revealed in protargol preparations, appears to be more rectangular than that of T. hominis, but may be wedged-shaped in side view. The axostyle is of the same type as that of T. hominis, but appears to be wider, and outside the body tapers more abruptly to its sharp posterior tip. The cytostome is inconspicuous. In swimming, T. microti is more erratic, less vigorous and less progressive than T. hominis. Originally obtained from Microtis pennsylvanicus, T. microti was successfully transferred to rats, guinea pigs and hamsters. It was found also on stained slides from a wild Peromyscus leucopus, a wild Rattus norvegicus and several hamsters (Mesocricetus auratus). A human volunteer who swallowed a culture did not become infected. It was successfully cultured at 32-33[degree]C and at room temp.