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

PLoS Negl Trop Dis. 2021 Apr 19;15(4):e0009288. doi: 10.1371/journal.pntd.0009288. eCollection 2021 Apr.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Armenia / epidemiology
  • Child, Preschool
  • Communicable Diseases, Emerging / diagnosis*
  • Communicable Diseases, Emerging / epidemiology
  • Communicable Diseases, Emerging / parasitology
  • Ecosystem
  • Female
  • Genotype
  • Humans
  • Infant
  • Leishmania infantum / genetics*
  • Leishmaniasis, Visceral / diagnosis*
  • Leishmaniasis, Visceral / epidemiology*
  • Leishmaniasis, Visceral / parasitology
  • Male
  • Microsatellite Repeats*
  • Molecular Epidemiology
  • Molecular Typing
  • Pilot Projects
  • Polymorphism, Restriction Fragment Length
  • Risk Assessment

Grants and funding

This work was supported by grants from the Federal Ministry of Education and Research of Germany (Bundesministerium für Bildung und Forschung – 01DK14021 and 16PGF0170) awarded to KK. Additional support from the German Academic Exchange Service (Deutscher Akademischer Austauschdienst – DAAD – Research grant 1618841 awarded to AS) and the Foundation for Science and Technology (FCT) Portugal (Fundação para a Ciência e a Tecnologia – IF/0773/2015 awarded to SC) is gratefully acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.