GENETIC DIVERSITY IN NATURAL-POPULATIONS OF NEW-WORLD LEISHMANIA

Our results have shown the wide diversity of parasites within New Worl d Leishmania. Biochemical and molecular characterization of species wi thin the genus has revealed that much of the population heterogeneity has a genetic basis. The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, alth ough occasional bouts of sexual reproduction can not be ruled out. Gen etic variation is extensive with some clones widely distributed and ot hers seemingly unique and localized to a particular endemic focus. Epi demiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particul arly in localized areas. Future research using molecular techniques sh ould aim to identify and follow Leishmania types in nature and correla te genetic typing with important clinical characteristics such as viru lence, pathogenicity, drug resistance and antigenic variation. The epi demiological significance of such variation not only has important imp lications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents.