MOLECULAR KARYOTYPE CHARACTERIZATION OF LEISHMANIA-PANAMENSIS, LEISHMANIA-MEXICANA, AND LEISHMANIA-MAJOR LIKE PARASITES - AGENTS OF CUTANEOUS LEISHMANIASIS IN ECUADOR

Molecular karyotypes of Leishmania isolates from patients with cutaneo us leishmaniasis in Ecuador were analyzed by pulsed-field gel electrop horesis (PFGE) and Southern blot hybridization. The DNA karyotypes of L. major-like parasites were similar between two human isolates from a lowland coastal and a highland Andean region, but were apparently dif ferent from those of eleven World Health Organization reference strain s including L. major. The smallest chromosome of 240 kilobases in L. m ajor-like parasites was found to belong to the 715-class of small line ar chromosomal DNAs, which have been shown to appear in some lines of Leishmania. Chromosome banding patterns of L. mexicana isolates exhibi ted a novel, ordered, chromosomal ladder, and were identical among fou r human isolates and one canine isolate from a restricted geographic r egion in the Andes. On the other hand, minor chromosome size polymorph isms were observed among three L. panamensis isolates from different e ndemic regions near the Pacific Coast. Chromosomal locations of dihydr ofolate reductase-thymidylate synthetase and P-glycoprotein genes reve aled further differences in chromosomal organizations among these Leis hmania species in Ecuador. These results indicate that karyotype analy sis by PFGE is useful for epidemiologic studies of leishmaniasis in Ec uador.