Microscopy

Amastigotes of Leishmania are spherical to ovoid and measure 1-5 µm long by 1-2 µm wide.  They possess a large nucleus, a prominent kinetoplast, and a short axoneme, the last of which is rarely visible by light microscopy.  The organisms reside in macrophages of the host and can be found throughout the body.

A	B

A, B:  Leishmania spp. amastigotes; touch-prep stained with Giemsa.

D

C:  Leishmania mexicana in a biopsy specimen from a skin lesion stained with hematoxylin and eosin.  The amastigotes are lining the walls of two vacuoles, a typical arrangement.  The species identification was derived from culture followed by isoenzyme analysis.  Infection was acquired in Texas.