Which stage resides intracellularly within macrophages as part of the Leishmania life cycle?

Which stage resides intracellularly within macrophages as part of the Leishmania life cycle?

• A. Amastigote
• B. Promastigote
• C. Epimastigote
• D. Trypomastigote

Answer: (A)

Inside macrophages, Leishmania exists as the amastigote form. This intracellular, non‑flagellated stage is adapted to live in the acidified phagolysosome and replicates there by binary fission, driving the tissue infection you see in leishmaniasis. The promastigote is the flagellated form found in the sandfly and the early stage after transmission, before the parasite is taken up by macrophages and transforms. Epimastigote and trypomastigote are forms associated with other kinetoplastid parasites and are not the intracellular macrophage-residing stage in Leishmania.

Inside macrophages, Leishmania exists as the amastigote form. This intracellular, non‑flagellated stage is adapted to live in the acidified phagolysosome and replicates there by binary fission, driving the tissue infection you see in leishmaniasis. The promastigote is the flagellated form found in the sandfly and the early stage after transmission, before the parasite is taken up by macrophages and transforms. Epimastigote and trypomastigote are forms associated with other kinetoplastid parasites and are not the intracellular macrophage-residing stage in Leishmania.