Electron microscopical studies on cutaneous leishmaniasis in Ethiopia

Lesions of two Ethiopian patients suffering from diffuse cutaneous leishmaniasis were monitored by electron microscopy. The appearance of the Leishmania and host cells was generally similar in both cases although minor differences were detectable. The mean long diameter of the parasites was similar: 2·32 μm (±0·17 S.D.) and 2·23 μm (±0·7 S.D.) in cases (i) and (ii), respectively. The mean interdistance of the pellicular microtubulus was almost identical at 51–52 nm. The parasites were localized in parasilophorous vacuoles and/or singly within the cytoplasm, though to a different extent in the two cases. The vacuolar parasites tended to make close contact with the vacuolar membrane. The cytoplasmic parasites were never ‘free’, but surrounded by two unit membranes, with the parasitic plasma membrane closely apposed to the remnant vacuolar membrane. Daily injections of pentamidine for two weeks produced a considerable fall in parasite numbers. Some parasites showed internal changes, but most were not visibly affected after this treatment. Pentamidine destroys both host cells and non-parasitized dermal cells.