Francisella tularensis, a small Gram-negative bacterium, is capable of infecting a wide range of animals, including humans, and causes a plague-like disease called tularemia—a highly contagious disease with a high mortality rate. Because of these characteristics, F. tularensis is considered a potential agent of biological terrorism. Currently, F. tularensis is divided into four subspecies, which differ in their virulence and geographic distribution. Two of them, subsp. tularensis (primarily found in North America) and subsp. holarctica (widespread across the Northern Hemisphere), are responsible for tularemia in humans. Subsp. novicida is almost avirulent in humans. The fourth subspecies, subsp. mediasiatica, is the least studied because of its limited distribution and impact in human health. It is found only in sparsely populated regions of Central Asia. In this report, we describe the first focus of naturally circulating F. tularensis subsp. mediasiatica in Russia. We isolated and characterized 18 strains of this subspecies in the Altai region. All strains were highly virulent in mice. The virulence of subsp. mediasiatica in a vaccinated mouse model is intermediate between that of subsp. tularensis and subsp. holarctica. Based on a multiple-locus variable number tandem repeat analysis (MLVA), we show that the Altaic population of F. tularensis subsp. mediasiatica is genetically distinct from the classical Central Asian population, and probably is endemic to Southern Siberia. We propose to subdivide the mediasiatica subspecies into three phylogeographic groups, M.I, M.II and M.III.
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, and whole genome sequence analysis showed that it is most closely related to the Yamal strains in spite of the remoteness of Yamal from Yakutia. The two other strains contribute to two different branches of A.Br.008/011, one of the remarkable polytomies described so far in the B . anthracis species. The geographic distribution of the strains belonging to A.Br.008/011 is suggesting that the 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.
Проблемы особо опасных инфекций. 2016, вып. 4 42 Problemy Osobo Opasnykh Infektsii [Problems of Particularly Dangerous Infections]сибирская язва -особо опасная бактериальная зоонозная инфекция, способная благодаря длитель-ному сохранению в почве спор Bacillus anthracis со-хранять угрозу возвращения и повторных вспышек на пораженных территориях в течение многих деся-тилетий. основным источником инфекции для чело-века является больное животное или его труп, факто-рами передачи -продукты животноводства, почва и другие объекты окружающей среды.на территории российской Федерации насчиты-вается свыше 35 тыс. стационарно неблагополучных по сибирской язве пунктов (снп), в которых учте-но около 8 тыс. сибиреязвенных скотомогильников. при этом существует высокая вероятность наличия значительного количества неучтенных сибиреязвен-ных захоронений [2]. за последние 20 лет, в период с 1996 по 2015 год, в российской Федерации. по сравнению с пред-ыдущим двадцатилетним периодом (1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995) в 2016 г. на территории ямало-ненецкого автономного округа возникла эпидемия сибирской язвы, при этом заболело 2650 северных оленей. в результате контакта с больными и павшими животными за-болело 36человек с одним летальным исходом. проведенный в полном объеме комплекс противоэпиде-мических, противоэпизоотических и профилактических мероприятий, оперативная организация работы на региональном уровне позволили в максимально короткие сроки локализовать крупный очаг сибирской язвы. на основании опыта работы во время вспышки определены пути дальнейшего совершенствования эпидемиологического надзора и профилактики сибирской язвы в современных условиях.Ключевые слова: сибирская язва, эпизоотия, северные олени, противоэпидемические мероприятия. In 2016, in the territory of Yamalo-Nenets Autonomous District an outbreak of anthrax took place, 2650 reindeers were infected. As a consequence of contacts with affected and fallen animals, 36 cases of human infection occurred, of which one was fatal. Performed full-extent complex of anti-epidemic, anti-epizootic, and preventive measures, prompt organization of operations at the regional level allowed for localization of large-scale anthrax focus within the minimum possible time. Based on the lessons learned, identified were the ways to further enhancement of epidemiological surveillance and prophylaxis of anthrax under current conditions.
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.
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
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