The ultrastructure of Leishmania tropica in skin lesions.

The ultrastructure of the amastigote stage of Leishmania tropica has been studied. The present work reports on new observations on the fine structure of the basal body, prokinosome and flagellum. The basal body is composed of a centriole-like structure and a transitional zone continuous with the proximal part of the flagellum. The centriole-like part consists of nine peripheral triplet tubules and an indistinct dense central core. The transitional zone consists of nine peripheral doublet tubules and two central cylinders. The centriole-like prokinosome is present parallel and close to the basal body. The flagellum arises from the transitional zone of the body and has the classical axoneme (9+2) structure. However, at the tip of the flagellum the central tubules are replaced by one of the peripheral doublet tubules. The ultrastructural findings, as compared with previous studies of Leishmania, are discussed.