EPIDEMIOLOGIC, GENETIC, AND CLINICAL ASSOCIATIONS AMONG PHENOTYPICALLY DISTINCT POPULATIONS OF LEISHMANIA (VIANNIA) IN COLOMBIA

Phenotypic characterization of 511 strains of Leishmania, subgenus Via nnia, isolated from Colombian patients was conducted based on electrop horetic polymorphisms of 13 isoenzymes. Ninety-one Colombian strains o f L. braziliensis were the most heterogeneous, constituting seven zymo demes while 397 L. panamensis and 22 L. guyanensis strains yielded fiv e and three zymodemes, respectively. Phosphogluconate dehydrogenase, n ucleoside hydrolase, and superoxide dismutase were the most polymorphi c enzymes in this collection of strains, and together with glucose-6-p hosphate dehydrogenase, allowed the discrimination of the three aforem entioned species. Hierarchical cluster analysis of the zymodemes using Jaccard's coefficient of similarities revealed two clusters, one cons tituted by L. braziliensis zymodemes, and another by three subgroups c onsisting of zymodemes of L. panamensis closely related to the species reference strain, another consisting of L. guyanensis zymodemes, and a third group distinguished by new electromorphs of proline iminopepti dase and aspartate aminotransferase that reacted with the L. panamensi s-specific monoclonal antibody B-ll. Multiple zymodemes of L. panamens is and L. guyanensis were found to be sympatrically transmitted in foc i along the Pacific coast. Leishmania braziliensis variants were ubiqu itous throughout the territory of Colombia; L. panamensis was prevalen t in the western region and L. guyansis was prevalent in the Orinoco a nd Amazon river basins in the eastern half of the country. Distinct zy modemes of L. panamensis predominated in the northern and southern reg ions of the Pacific coast. Nine zymodemes of all three species were is olated from mucosal lesions. Zymodeme 1.1 of L. braziliensis had the h ighest frequency of mucosal involvement (10% of the cases), and diseas e caused by this zymodeme had the longest mean time of evolution (31 m onths; P = 0.002). In addition to being useful in describing epidemiol ogic relationships, the intraspecific heterogeneity of strains of the Viannia subgenus within and among foci can be used to understand such fundamental questions as the pathogenicity of different populations of parasites, and the induction of cross-protection against related para sites.