<unk>  is a unicellular eukaryote having a well-defined nucleus and other cell organelles including a kinetoplast and a flagellum. This species has n=36 chromosomes. Depending on its host it exists in two structural variants, as follows: #Amastigote form found in the mononuclear phagocyte and circulatory systems of humans. It is an intracellular and non-motile form, being devoid of external flagellum. The short flagellum is embedded in the anterior end without projecting out. It is oval in shape, and measures 3–6 μm in length and 1–3 μm in breadth. The kinetoplast and basal body lie towards the anterior end. #Promastigote is formed in the alimentary tract of the sandfly. It is an extracellular and motile form. It is considerably larger and more highly elongated, measuring 15–30 μm in length and 5 μm in width. It is spindle-shaped, tapering at both ends. A long flagellum (about the body length) is projected externally at the anterior end. The nucleus lies at the centre, and in front of which are kinetoplast and basal body.
Leishmania donovani
Leishmania braziliensis
Leishmania major
Leishmania mexicana
Leishmania infantum
Leishmania amazonensis
Trypanosoma brucei
Brugia malayi