PLoS Neglected Tropical Diseases (Jun 2011)

Comparative microsatellite typing of new world leishmania infantum reveals low heterogeneity among populations and its recent old world origin.

  • Katrin Kuhls,
  • Mohammad Zahangir Alam,
  • Elisa Cupolillo,
  • Gabriel Eduardo M Ferreira,
  • Isabel L Mauricio,
  • Rolando Oddone,
  • M Dora Feliciangeli,
  • Thierry Wirth,
  • Michael A Miles,
  • Gabriele Schönian

DOI
https://doi.org/10.1371/journal.pntd.0001155
Journal volume & issue
Vol. 5, no. 6
p. e1155

Abstract

Read online

Leishmania infantum (syn. L. chagasi) is the causative agent of visceral leishmaniasis (VL) in the New World (NW) with endemic regions extending from southern USA to northern Argentina. The two hypotheses about the origin of VL in the NW suggest (1) recent importation of L. infantum from the Old World (OW), or (2) an indigenous origin and a distinct taxonomic rank for the NW parasite. Multilocus microsatellite typing was applied in a survey of 98 L. infantum isolates from different NW foci. The microsatellite profiles obtained were compared to those of 308 L. infantum and 20 L. donovani strains from OW countries previously assigned to well-defined populations. Two main populations were identified for both NW and OW L. infantum. Most of the NW strains belonged to population 1, which corresponded to the OW MON-1 population. However, the NW population was much more homogeneous. A second, more heterogeneous, population comprised most Caribbean strains and corresponded to the OW non-MON-1 population. All Brazilian L. infantum strains belonged to population 1, although they represented 61% of the sample and originated from 9 states. Population analysis including the OW L. infantum populations indicated that the NW strains were more similar to MON-1 and non-MON-1 sub-populations of L. infantum from southwest Europe, than to any other OW sub-population. Moreover, similarity between NW and Southwest European L. infantum was higher than between OW L. infantum from distinct parts of the Mediterranean region, Middle East and Central Asia. No correlation was found between NW L. infantum genotypes and clinical picture or host background. This study represents the first continent-wide analysis of NW L. infantum population structure. It confirmed that the agent of VL in the NW is L. infantum and that the parasite has been recently imported multiple times to the NW from southwest Europe.