The life cycle of Leishmania amazonensis (A), and structural organization of the promastigote (B) and amastigote (C) forms.

(A) The female sandfly (1) insect bites an infected mammal during the blood meal. Infected macrophages (2) with amastigote forms. (3) Amastigote form. (4) Amastigotes transform into procyclic promastigotes. (5) Procyclic promastigotes multiply in the midgut. (6) Promastigotes migrate toward the stomodeal valve in the anterior midgut and re-initiate cell division. (7) Promastigotes transform into infective metacyclic promastigotes. (8) The female sandfly releases the metacyclic promastigotes into a new mammalian host via regurgitation during the blood meal. (9) Metacyclic promastigotes. (10) Metacyclic promastigotes infect macrophages. (11) Metacyclic promastigotes transform into amastigotes. (12) Amastigotes attach to the membrane of the parasitophorous vacuole. (13) Amastigotes multiply in the vacuole. (14) Intense amastigote multiplication. (15) Amastigotes burst out of the cell. (16) Amastigote form. (17) An amastigote infects a macrophage. In the central portion of the figure, we added the most important reservoirs involved in the maintenance of the parasite. Schematic 3D representations of the organelles found in the Leishmania promastigote (B) and amastigote (C).