THE PATHOLOGY OF CUTANEOUS LEISHMANIASIS IN THE SUDAN - A COMPARISON WITH THAT IN OTHER GEOGRAPHICAL AREAS

The pathology of cutaneous leishmaniasis (CL) caused by Leishmania maj or zymodeme LON 1 in the Sudan was compared with that caused by L. maj or zymodeme LON 4 in Saudi Arabia and with that already described for L. tropica infections in Iran and for localized CL in the New World. T he lesions were classified according to Ridley's five histological typ es. Most of the lesions in the Sudan and Saudi Arabia were of types B and C, characterized, respectively, by diffuse macrophage necrosis and focalized necrosis. B was the most common type in Nicaragua and Guyan a whereas responses of types A (in which there are heavily parasitized macrophages without necrosis) and D (reactive tuberculoid) were the m ost frequent in Iran. The type-E response, which is similar to D but w ith virtual absence of plasma cells, was uncommon in all areas. The ty pe-D reaction is a chronic relapsing disease when associated with L. t ropica but not when associated with L. major. The major differences in the pathology of CL in different geographical areas most probably rel ate to differences in the Leishmania species involved. Minor differenc es, however, not only occur between patients from the same area but ma p also occur, with time, in the same patient. Detailed comparison betw een areas is therefore difficult; lesions on one patient may heal asyn chronously and show different histological types at any point in time and rebiopsy from the same lesion during healing reveals changes from one histological type to another.