Molecular epidemiology and population genetics in Leishmania.

Abstract

Polymorphic DNA sequences have been amplified using different PCR-based techniques and used for species identification, strain discrimination and population genetic studies in Leishmania. A PCR fingerprinting method that uses single non-specific primers generates species-specific banding patterns with some intraspecies variation. This approach can be used to identify Leishmania species and also to discriminate strains of different Leishmania species. Cultivation of the parasites is, however, mandatory. PCR-restriction fragment length polymorphism of the internal transcribed spacer (ITS) in the ribosomal operon differentiates all Leishmania species, except members of the L. donovani and L. brasiliensis complexes. ITS-single-strand conformation polymorphism or ITS sequencing can detect strain specific-variation (except in L. infantum); culturing is not required. Species of Leishmania exhibit different degrees of genetic variation (L. tropica > L. aethiopica > L. major > L. donovani). Population analysis using co-dominant DNA markers developed by sequence-confirmed amplified region analysis revealed a primarily clonal structure in a L. donovani population from Sudan and suggested that occasional recombination events may occur in this population.