Molecular epidemiology and population genetics in Leishmania

Polymorphic DNA sequences have been amplified using different PCR-based tec hniques and used for species identification, strain discrimination and popu lation genetic studies in Leishmania. A PCR fingerprinting method that uses single non-specific primers generates species-specific banding patterns wi th some intraspecies variation. This approach can be used to identify Leish mania species and also to discriminate strains of different Leishmania spec ies. Cultivation of the parasites is, however, mandatory. PCR-restriction f ragment 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 conformati on polymorphism or ITS sequencing can detect strain specific-variation (exc ept in L. infantum); culturing is not required. Species of Leishmania exhib it different degrees of genetic variation (L. tropica > L. aethiopica > L. major > L, donovani). Population analysis using co-dominant DNA markers dev eloped 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.