Análise de isolados de Leishmania major-like por abordagens de genômica comparativa

Abstract

Leishmaniasis are caused by parasites belonging to the Leishmania genus and encompass a varied clinical manifestations depending on the species associated with the infection and the host immune response. Leishmania (Leishmania) major is an important agent of cutaneous leishmaniasis in the Old World, having as vector sand flies belonging to the Phlebotomus genus. In the New World, the species Leishmania (L.) mexicana, L. (L.) amazonensis e L. (L.) venezuelensis, Leishmania (Viannia) braziliensis, L. (V.) panamensis, L. (V.) guyanensis, L. (V.) peruviana are the main etiologic agents of cutaneous leishmaniasis. However, in some American countries, as Brazil, Venezuela, Peru, Paraguai, Equador and México, some parasites similar to L. major have been isolated from patients that have never been outside their countries. These parasites were named “L. major-like”, and several studies have been carried out to characterize these isolates biochemically, molecularly and biologically, however it is still unknown whether they were recently imported from the Old World or if they were originated in the Americas. Besides, there are no genome-wide studies involving L. major-like isolates, which hampers our understanding of their biology and phylogeny and could also contribute to the understanding of the genetic basis of mechanisms underlining the differences observed in their infectivity. Therefore, in the present study, we characterized three L. major-like isolates, named BH49, BH121 and BH129, using whole-genome approaches. Phylogenetic analysis including L. major isolates from Old World and species that cause tegumentar leishmaniasis in the New World were included in our analyses in order to better understand the taxonomic classification of these L. major-like isolates and to investigate if these parasites were originated from strains here in America or if they were imported from the Old World. Besides, we evaluated the presence of gene and segmental duplications/deletions, presence of aneuploidies and SNPs in virulence factors that could explain the difference of infectivity observed in these isolates. Finally, from genomic data, we have searched for biomarkers that could be used in the genotyping or sorotyping of these isolates.