Genetic Diversity in Natural Populations of New World

Our results have shown the wide diversity of parasites within New World Leishmania. Biochemical and molecular characterization of species within 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, although occasional bouts of sexual reproduction can not be ruled out. Genetic variation is extensive with some clones widely distributed and others seem-ingly unique and localized to a particular endemic focus. Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas. Future research using molecular techniques should aim to identify and follow Leish-mania types in nature and correlate genetic typing with important clinical characteristics such as viru-lence, pathogenicity, drug resistance and antigenic variation. The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents. Key words: New World Leishmania- leishmaniasis- epidemiology- molecular characterization Genetic variation in medically important pro-tozoan parasites and the nature of the reproductive strategies which predispose to such variation are currently the subject of much interest and contro