Insights from Bacillus anthracis strains isolated from permafrost in the tundra zone of Russia

Abstract

20This article describes Bacillus anthracis strains isolated during an outbreak of anthrax on 21 the Yamal Peninsula in the summer of 2016 and independently in Yakutia in 2015. A common 22 feature of these strains is their conservation in permafrost, from which they were extracted either 23 due to the thawing of permafrost (Yamal strains) or as the result of paleontological excavations 24 (Yakut strains). All strains isolated on the Yamal share an identical genotype belonging to lineage 2 25 B.Br.001/002, pointing to a common source of infection in a territory over 250 km in length. In 26 contrast, during the excavations in Yakutia, three genetically different strains were recovered from 27 a single pit. One strain belongs to B.Br.001/002, as the Yamal strains. Despite the remoteness of 28 Yamal from Yakutia, whole genome sequence analysis showed that the B.Br.001/002 strains are 29 very closely related. The two other strains contribute to two different branches of A.Br.008/011, 30 one of the remarkable polytomies described so far in B. anthracis population. The geographic 31 distribution of the strains belonging to this polytomy is suggesting that this polytomy emerged in 32 the thirteenth century, in combination with the constitution of a unified Mongol empire extending 33 from China to Eastern Europe. We propose an evolutionary model for B. anthracis recent evolution 34 in which the B lineage spread throughout Eurasia and was subsequently replaced by the A lineage 35 except in some geographically isolated areas.36

A Review of Arguments for the Existence of Latent Infections of Bacillus anthracis, and Research Needed to Understand Their Role in the Outbreaks of Anthrax

“…Reindeers have suffered massively from anthrax outbreaks. Soviets vaccinated domestic animals in Yamal from 1925–1945 and the disease disappeared for 75 years until a minor outbreak in 2016 [ 15 ].…”

Testing predictability of disease outbreaks with a simple model of pathogen biogeography

“…While both may be driven by genetic shifts in pathogens or changing land use patterns enhancing transmission risk, re-emergence events are more likely to be related to weakened healthcare infrastructure, prematurely terminated eradication campaigns [27,28] or low detection of long-term persistence of environmental pathogen reservoirs (e.g. anthrax spores in the soil and permafrost; [29,30]).…”

Routes of Spread of Anthrax in Natural Ecosystems

“…При этом они сохраняют жизнеспособность и, что более важно, вирулентность в течение как минимум десятков и даже сотен лет. Место гибели животного от сибирской язвы сохраняет эпидемический потенциал, то есть на нем возможны новые вспышки заболевания [7,8].…”

“…Один из первых заболевших оленей вовремя получил инъекцию бициллина, через несколько часов после которой он пошел на поправку, смог самостоятельно подняться и был допущен аборигенами к животным, с которыми его до болезни постоянно запрягали в одну упряжку. Этот излеченный олень и ранее здоровые олени при встрече обнюхивали друг друга и терлись мордами, после чего здоровые олени практически одновременно заболели сибирской язвой и умерли через сутки [8]. Вероятно, имело место заражение через слизистые носа и глаз.…”