American tegumentary leishmaniasis: antigen-gene polymorphism, taxonomy and clinical pleomorphism

Multi-locus enzyme electrophoresis is the current gold standard for the genetic characterisation of Leishmania. However, this method is time-consuming and, more importantly, cannot be directly applied to parasites present in host tissue. PCR-based methods represent an ideal alternative but, to date, a multi-locus analysis has not been applied to the same sample. This has now been achieved with a sample of 55 neotropical isolates (Leishmania (Viannia) braziliensis, L. (V.) peruviana, L. (V.) guyanensis, L. (V.) lainsoni and L. (L.) amazonensis), using five different genes as targets, four of which encoded major Leishmania antigens (gp63, Hsp70, H2B and Cpb). Our multi-locus approach strongly supports the current taxonomy and demonstrates a highly robust method of distinguishing different strains. Within L. (V.) braziliensis, we did not encounter so far specific genetic differences between parasites isolated from cutaneous and mucosal lesions. Interestingly, results provided by each of the different antigen-genes in the species considered, were different, suggesting different selective pressures. Our work emphasises the need for a multi-disciplinary approach to study the clinical pleomorphism of leishmaniasis.