Ultrastructural studies on cutaneous leishmaniasis in Ecuador.

Resumen

Ultrastructural observations were made of the lesions of three Ecuadorian patients with cutaneous leishmaniasis. Parasites were located both within the macro-phages, either inside the intracytoplasmic vacuoles (parasitophorous vacuoles) or free in cytoplasm and outside host cells. Amastigotes were rounded or oval with a mean length of 2.62 μm (±0.17 S.D.) and mean width of 2.18μm (±0.28 S.D.). Parasites showed degeneration intracellularly both within the vacuoles and in the cytoplasm of macro-phages. Lymphocytes were seen in close contact with parasitized macrophages as well as directly attached to the parasites. Furthermore, spongiotic vesicle was observed in the epidermis where Leishmania parasites were found, surrounded by lymphocytes and other mononuclear cells. Amastigotes attached to mononuclear cells were also observed inside and between the keratinocytes. Mononuclear cells containing melanin granules showed amastigotes in their cytoplasm.The parasite-macrophage relationship, the role of T-cells in combating the parasites and the fate of the parasites inside the host body are discussed.