Anthrax is an especially dangerous zooanthroponosis caused by the Gram-positive spore-forming bacterium Bacillus anthracis. A notable feature of this disease is the difference in susceptibility to it among different groups of animals. Anthrax primarily affects herbivorous ungulate mammals; they are easily infected, and their disease often leads to rapid, even sudden, death. However, predators and scavengers are extremely resistant to anthrax, and if they become infected, they usually become mildly ill. As the result of the increased sensitivity of ungulates to anthrax and the possibility of disease transmission from them to humans, most studies of anthrax have focused on the diagnosis, prevention, and treatment of infection in farm animals and humans. The issues of anthrax in other animals, such as predators, and the peculiarities of anthrax epidemiology in wild ungulates have not been sufficiently detailed in the literature. In this article, we provide a review of literature sources that describe the differential susceptibility to infection of various groups of animals to anthrax and some epidemiological features of anthrax in animals that are not the main hosts of B. anthracis.

Tularemia is a severe infectious disease caused by the Gram-negative bacteria Fracisella tularensis. There are four subspecies of F.tularensis: holarctica, tularensis, mediasiatica, and novicida, which differ in their virulence and geographic distribution. One of them, subsp. mediasiatica remains extremely poorly studied, primarily due to the fact that it is found only in the sparsely populated regions of Central Asia and Russia. In particular there is little information in the literature on the virulence and pathogenicity of subsp. mediasiatica. In the present article, we evaluated the comparative virulence of subsp. mediasiatica in vaccinated laboratory animals which we infected with virulent strains: subsp. mediasiatica 678, subsp. holarctica 503, and subsp. tularensis SCHU within 60 to 180 days after vaccination. We found that subsp. mediasiatica is comparable in pathogenicity in mice with subsp. tularensis and in guinea pigs with subsp. holarctica. We also found that the live vaccine does not fully protect mice from subsp. mediasiatica but completely protects guinea pigs for at least six months. In general, our data suggest that subsp. mediasiatica occupies an intermediate position in virulence between spp. tularensis and holarctica.

Anthrax is a particularly dangerous infection of humans and ungulates caused by the Gram-positive spore-forming bacterium Bacillus anthracis. The highly monomorphic and clonal species B. anthracis is commonly divided into three main lineages, A, B, and C, which in turn are divided into several canSNP groups. We report here a phylogenetic analysis based on the whole-genome sequence (WGS) data of fifteen strains isolated predominantly in Siberia or Central and Southern Russia. We confirm the wide distribution of the cluster of strains of the B.Br.001/002 group, endemic to the Russian Arctic, which is also present in the steppe zone of Southern Siberia. We characterize additional branches within the major A.Br.001/002 polytomy comprising the A.Br.Ames and A.Br.Sterne lineages, one of which is identified in the Arctic.

The main pathogenic factor of Bacillus anthracis is a three-component toxin encoded by the pagA, lef, and cya genes, which are located on the pXO1 plasmid. The atxA gene, which encodes the primary regulator of pathogenicity factor expression, is located on the same plasmid. In this work, we evaluated the polymorphism of the pagA, lef, cya, and atxA genes for 85 B. anthracis strains from different evolutionary lineages and canSNP groups. We have found a strong correlation of 19 genotypes with the main evolutionary lineages, but the correlation with the canSNP group of the strain was not as strong. We have detected several genetic markers indicating the geographical origin of the strains, for example, their source from the steppe zone of the former USSR. We also found that strains of the B.Br.001/002 group caused an anthrax epidemic in Russia in 2016 and strains isolated during paleontological excavations in the Russian Arctic have the same genotype as the strains of the B.Br.CNEVA group circulating in Central Europe. This data could testify in favor of the genetic relationship of these two groups of strains and hypothesize the ways of distribution of their ancestral forms between Europe and the Arctic.

Tularemia is a severe infectious disease caused by the Gram-negative bacteria Francisella tularensis. F. tularensis is currently divided into three subspecies, holarctica, tularensis, and mediasiatica, which differ in their virulence and geographic distribution. Subspecies mediasiatica is the least studied because of its very low documented virulence for humans and limited geographic distribution. It was discovered in sparsely populated regions of Central Asia. Since 2011, a new subsp. mediasiatica lineage was identified in Altai (Russia). In 2021, we isolated one subsp. mediasiatica strain in Krasnoyarsk Territory. In spite of its geographic origin, 500 km east from Altai, this strain belongs to the Altai lineage and contributes surprisingly little genetic diversity to previous knowledge.

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