Genetic diversity and structure in Leishmania infantum populations from southeastern Europe revealed by microsatellite analysis

WOS: 000328837200003PubMed ID: 24308691Background: The dynamic re-emergence of visceral leishmaniasis (VL) in south Europe and the northward shift to Leishmania-free European countries are well-documented. However, the epidemiology of VL due to Leishmania infantum in southeastern (SE) Europe and the Balkans is inadequately examined. Herein, we aim to re-evaluate and compare the population structure of L. infantum in SE and southwestern (SW) Europe. Methods: Leishmania strains collected from humans and canines in Turkey, Cyprus, Bulgaria, Greece, Albania and Croatia, were characterized by the K26-PCR assay and multilocus enzyme electrophoresis (MLEE). Genetic diversity was assessed by multilocus microsatellite typing (MLMT) and MLM Types were analyzed by model- and distance-based algorithms to infer the population structure of 128 L. infantum strains. Results: L. infantum MON-1 was found predominant in SE Europe, whilst 16.8% of strains were MON-98. Distinct genetic populations revealed clear differentiation between SE and SW European strains. Interestingly, Cypriot canine isolates were genetically isolated and formed a monophyletic group, suggesting the constitution of a clonal MON-1 population circulating among dogs. In contrast, two highly heterogeneous populations enclosed all MON-1 and MON-98 strains from the other SE European countries. Structure sub-clustering, phylogenetic and Splitstree analysis also revealed two distinct Croatian subpopulations. A mosaic of evolutionary effects resulted in consecutive sub-structuring, which indicated substantial differentiation and gene flow among strains of both zymodemes. Conclusions: This is the first population genetic study of L. infantum in SE Europe and the Balkans. Our findings demonstrate the differentiation between SE and SW European strains; revealing the partition of Croatian strains between these populations and the genetic isolation of Cypriot strains. This mirrors the geographic position of Croatia located in central Europe and the natural isolation of the island of Cyprus. We have analysed the largest number of MON-98 strains so far. Our results indicate extensive gene flow, recombination and no differentiation between MON-1 and MON-98 zymodemes. No correlation either to host specificity or place and year of strain isolation was identified. Our findings may be associated with intensive host migration and common eco-epidemiological characteristics in these countries and give valuable insight into the dynamics of VL.GSRT-TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [SBAG-GSRT-23 (109S448)]This study was supported by the GSRT-TUBITAK grant [joint Research and Technology programmes 2010-2011, Greece-Turkey, Project no: SBAG-GSRT-23 (109S448)]. The authors also thank Dr. E. Dotsika (Laboratory of Cellular Immunology, Hellenic Pasteur Institute) for kindly providing strain BG1 and Dr. Teita Myrseli and Dr. Silva Bino (Control of Infectious Diseases Department, Institute of Public Health, Tirana, Albania) for providing Leishmania DNA for the strains AH2, AH4 and AD16. This work was in partial fulfillment of the requirements of Charite Universitatsmedizin in Berlin (Germany) toward the PhD of Ms Evi Gouzelou