Microsatellite based molecular epidemiology of Leishmania infantum from re-emerging foci of visceral leishmaniasis in Armenia and pilot risk assessment by ecological niche modeling.

BACKGROUND: Visceral leishmaniasis (VL) is re-emerging in Armenia since 1999 with 167 cases recorded until 2019. The objectives of this study were (i) to determine for the first time the genetic diversity and population structure of the causative agent of VL in Armenia; (ii) to compare these genotypes with those from most endemic regions worldwide; (iii) to monitor the diversity of vectors in Armenia; (iv) to predict the distribution of the vectors and VL in time and space by ecological niche modeling. METHODOLOGY/PRINCIPAL FINDINGS: Human samples from different parts of Armenia previously identified by ITS-1-RFLP as L. infantum were studied by Multilocus Microsatellite Typing (MLMT). These data were combined with previously typed L. infantum strains from the main global endemic regions for population structure analysis. Within the 23 Armenian L. infantum strains 22 different genotypes were identified. The combined analysis revealed that all strains belong to the worldwide predominating MON1-population, however most closely related to a subpopulation from Southeastern Europe, Maghreb, Middle East and Central Asia. The three observed Armenian clusters grouped within this subpopulation with strains from Greece/Turkey, and from Central Asia, respectively. Ecological niche modeling based on VL cases and collected proven vectors (P. balcanicus, P. kandelakii) identified Yerevan and districts Lori, Tavush, Syunik, Armavir, Ararat bordering Georgia, Turkey, Iran and Azerbaijan as most suitable for the vectors and with the highest risk for VL transmission. Due to climate change the suitable habitat for VL transmission will expand in future all over Armenia. CONCLUSIONS: Genetic diversity and population structure of the causative agent of VL in Armenia were addressed for the first time. Further genotyping studies should be performed with samples from infected humans, animals and sand flies from all active foci including the neighboring countries to understand transmission cycles, re-emergence, spread, and epidemiology of VL in Armenia and the entire Transcaucasus enabling epidemiological monitoring.

Re-Emerging foci of visceral leishmaniasis in Armenia - first molecular diagnosis of clinical samples.

Visceral leishmaniasis (VL) was firstly reported in Armenia in 1913. Following a considerable increase of the number of cases until the mid 1950s, the disease disappeared after 1969 and re-emerged in 1999. Scientific literature about VL in Armenia is available only in Russian or Armenian. This paper presents a historical overview about leishmaniasis in Armenia based on this literature as well as an epidemiological update since the re-emergence of the disease. In 1999-2016, 116 indigenous VL cases were recorded mainly in children in 8 of the 11 districts, however, VL is underreported because of lack of trained medical personal and diagnostic facilities. The aim of this work was to apply for the first time molecular diagnosis of VL in Armenia. Out of 25 VL suspected patients, 22 were positive by microscopy and polymerase chain reaction (PCR). Genotyping using internal transcribed spacer 1-PCR-restriction fragment length polymorphism and sequencing identified the causative agent of VL in Armenia as Leishmania infantum. The present work is an important step towards the inclusion of molecular techniques in the current diagnosis of VL in Armenia and the establishment of local molecular diagnostic facilities.