Natural Mega-Focus of Yersinia pestis Main Subspecies, Antique Biovar, Phylogenetic Line 4.ANT in Gorny Altai

Abstract

Objective of this study was to investigate the areal of Yersinia pestis strains of antique biovar, main subspecies, phylogenetic line 4.ANT, as well as to establish the borders and spatial structure of mega-focus in the territory of Gorny Altai. Materials and methods. Complex comprehensive analysis of the properties in Yersinia pestis strains of the main subspecies, circulating in Gorny Altai has been conducted. 33 out of them, isolated predominantly in 2012–2017 have been sequenced. Whole genome SNP analysis and search of marker SNPs was performed using Wombac 2.0 software package. Tree diagram was built applying Maximum Likelihood algorithm, using PhyML 3.1 software on the basis of HKY85 model. Results and conclusions. Based on the results of whole genome SNPs analysis of 33 endemic strains and creation of the tree diagram of Y. pestis strains, the presence of natural mega-focus of Y. pestis belonging to the main subspecies, antique biovar, phylogenetic line 4.ANT has been substantiated. Epizootic manifestations on multiple local areas, characterized by persistent autonomous nature of plague manifestations, are registered on an annual basis. Within the boundaries of the areal of Yersinia pestis main subspecies, antique biovar, phylogenetic line 4.ANT, existence of joint natural foci of Yersinia pestis belonging to non-main subspecies ssp. altaica and ulegeica is established. Location of natural foci of the main and non-main subspecies of Yersinia pestis in different altitudinal belts of the Altai Mountains Range on the whole provides for observed multi-host and multi-vector feature of epizootic manifestations. For the first time ever, the data on the areal of the main subspecies of plague microbe are used for setting the boundaries of its natural focus.