Multilocus Microsatellite Typing (MLMT) of Strains from Turkey and Cyprus Reveals a Novel Monophyletic <em>L. donovani</em> Sensu Lato Group

<div><h3>Background</h3><p>New foci of human CL caused by strains of the <em>Leishmania donovani</em> (<em>L. donovani</em>) complex have been recently described in Cyprus and the Çukurova region in Turkey (<em>L. infantum</em>) situated 150 km north of Cyprus. Cypriot strains were typed by Multilocus Enzyme Electrophoresis (MLEE) using the Montpellier (MON) system as <em>L. donovani</em> zymodeme MON-37. However, multilocus microsatellite typing (MLMT) has shown that this zymodeme is paraphyletic; composed of distantly related genetic subgroups of different geographical origin. Consequently the origin of the Cypriot strains remained enigmatic.</p> <h3>Methodology/Principal Findings</h3><p>The Cypriot strains were compared with a set of Turkish isolates obtained from a CL patient and sand fly vectors in south-east Turkey (Çukurova region; CUK strains) and from a VL patient in the south-west (Kuşadasi; EP59 strain). These Turkish strains were initially analyzed using the <em>K26</em>-PCR assay that discriminates MON-1 strains by their amplicon size. In line with previous DNA-based data, the strains were inferred to the <em>L. donovani</em> complex and characterized as non MON-1. For these strains MLEE typing revealed two novel zymodemes; <em>L. donovani</em> MON-309 (CUK strains) and MON-308 (EP59). A population genetic analysis of the Turkish isolates was performed using 14 hyper-variable microsatellite loci. The genotypic profiles of 68 previously analyzed <em>L. donovani</em> complex strains from major endemic regions were included for comparison. Population structures were inferred by combination of Bayesian model-based and distance-based approaches. MLMT placed the Turkish and Cypriot strains in a subclade of a newly discovered, genetically distinct <em>L. infantum</em> monophyletic group, suggesting that the Cypriot strains may originate from Turkey.</p> <h3>Conclusion</h3><p>The discovery of a genetically distinct <em>L. infantum</em> monophyletic group in the south-eastern Mediterranean stresses the importance of species genetic characterization towards better understanding, monitoring and controlling the spread of leishmaniasis in this region.</p>