Genetic heterogeneity and phylogenetic status of Leishmania (Leishmania) infantum zymodeme MON-1: epidemiological implications

Abstract

Leishmania (Leishmania) infantum zymodeme MON-1 is responsible for the majority of visceral leishmaniasis cases around the Mediterranean basin, albeit that it causes also cutaneous forms. The MON classification is based on starch gel multilocus enzyme electrophoresis (MLEE) typing. The aim of this work was to explore further the genetic diversity and phylogenetic status of this zymodeme by alternative typing techniques. Fourteen L. (L.) infantum/L. (L.) chagasi stocks identified as MON-1 by MLEE in reference laboratories, 3 L. infantum stocks attributed to other zymodemes (MON-24, MON-29, MON-33) and reference standard stocks belonging to other species (L. (L.) major, L. (L.) tropica and L. (L.) donovani) were characterized by 2 different markers: MLEE on cellulose acetate plates and Random Amplified Polymorphic DNA (RAPD). We have obtained 10 different genotypes with RAPD and 6 different genotypes with MLEE on cellulose acetate plates for the 14 L. infantum/L. chagasi MON-1 stocks studied. MLEE and RAPD data gave quite congruent phylogenetic results: L. infantum zymodeme MON-1 was shown to be polyphyletic and genetically heterogeneous. This work confirms the necessity of using different markers to build up a robust phylogeny. Finally the epidemiological and clinical implications of these results are discussed.