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The aim of the study was molecular-genetic identification and analysis of the phylogenetic relationship of Yersinia pestis strains isolated on the Ukok Plateau in 2020, in order to establish the current boundaries of the natural mega focus of plague in the Altai Mountains in Russia and Mongolia.Materials and methods. 37 strains of Y. pestis of the main subspecies isolated in the Tuva mountain and Gorno-Altai high-mountain plague foci and adjacent territories of Mongolia in 1971–2020 were studied. The whole genome sequencing of the strains was performed using the Ion S5 XL System (Thermo Fischer Scientific). Ion Torrent Suite software package 5.12 and Newbler gsAssembler 2.6 were used to process the data and assemble de novo the sequences of raw reads. The average size of the collected genome was 4.55 million base pairs. Core SNPs were detected by aligning the contigs of Y. pestis strains on the CO92 genome using the Snippy 4.6 program, then 28 SNP homoplasies were removed. The resulting set of SNPs contained only the core region of the genome (955 SNPs). The dendrogram was constructed using the Maximum Likelihood method applying the PhyML 3.1 program.Results and discussion. The current population structure of Y. pestis of the main subspecies, antique biovar, phylogenetic line 4.ANT, endemic to the foci of the Altai Mountains in Russia and Mongolia has been determined. The presence of 4.ANT-21 clone, which became widespread in the territory of these natural foci of plague at the begining of the XXI century, was revealed. It is shown that three strains isolated on the Ukok Plateau in 2020 belong to clone 4.ANT-21. According to phylogenetic analysis, evidence of 4.ANT circulation on the Ukok Plateau before 2018 was obtained. The lesson that has been learned is that it is necessary to study the territories of Mongolia, Kazakhstan and China bordering the Ukok Plateau in order to establish the current boundaries of the 4.ANT mega focus.

The review presents the materials on the use of mobile laboratories, developed in the Russian Federation, in the framework of four main areas: monitoring of territories to identify the circulation of pathogens of natural-focal infectious diseases; monitoring of territories during the exacerbation of the epizootic situation; participation in the elimination of outbreaks of infectious diseases; monitoring of territories to control and predict the epidemiological and epizootiologic situation in preparation for mass events. The tactical and technical characteristics and the procedure for organizing the operation of the mobile laboratory for monitoring and diagnostics mounted on the platform of the KamAZ chassis are considered. A distinctive feature of the laboratory from the existing Russian and foreign counterparts is the availability of the necessary conditions for conducting research using bacteriological analysis, rapid and accelerated diagnostic methods, and performing a full cycle of works – from the preparatory stage to the destruction of infected material. Hightech equipment allows the realization of two research schemes: the first – bacteriological analysis alongside the PCR, which ensures high reliability of the results; the second – conducting the PCR at the first stage, and when identifying genetic markers of the pathogen – performing bacteriological analysis of positive samples in order to isolate the culture of the pathogen and identify it subsequently. The second scheme will reduce the volume of bacteriological studies; make changes in the tactics of epizootiological survey. Tests of the mobile laboratory have demonstrated the effectiveness of its use in the epizootiological examination of natural plague foci, including cross-border ones. Owing to the use of a mobile laboratory in the Gorno-Altaisk high-mountain natural focus of plague, a new epizootic site was identified, located in a remote area, used by the population as a summer pasture for grazing domestic animals. The use of mobile laboratories will strengthen the laboratory base of institutions that monitor particularly dangerous, natural-focal and other dangerous infectious diseases; will help to bring the advanced diagnostic technologies directly to the natural focus, reduce the risk of epidemic complications due to plague and other particularly dangerous infections in cross-border natural foci.

Objectiveof the study was monitoring of epizootic situation in the Mongolian part of the trans-boundary Sailugem natural plague focus through 2018 for optimization of preventive and anti-epidemic activities to decrease the level of risk of human plague cases among the population in the border areas of Mongolia and Russia.Materials and methods. Epizootic survey was conducted across the area of 2668 km2 ; 282 mammals, 261 ectoparasites, including 257 fleas, were tested for plague. All laboratory investigations of the field material were carried out in the mobile laboratory for monitoring and diagnostics, mounted on the platform of KAMAZ. Field samples were subjected to molecular-genetic (PCR) and serological tests. Fresh and mummified pickings of birds of prey, corpses, caught rodents and lagomorphs, fleas collected from corpses, were tested using immune-chromatographic method (ICM) to detect capsular antigen (F1) of plague microbe. PCR and ICM positive samples were investigated applying bacteriological method. In the course of epizootiological survey, GIS-tools were employed. All the results obtained were plotted on electronic maps using QGIS 2.12.3 software package.Results and discussion. The total of 47 Yersinia pestis ssp. pestis strains were isolated from grey marmots and their fleas. Y. pestis DNA was detected in 60 objects. Serological testing showed 60 positive results. Contamination of the caught souslik with plague agent reached 4.5 % (n=22), fresh corpses and picking of predatory birds – 63.4 % (n=41), mummified corpses and leftovers, skeletal remains – 10.0 % (n=140). It was established that in the border territory, adjacent to Russia, an intensive diffused plague epizooty, caused by the agent of the main subspecies, takes place. All epizootic manifestations were revealed at the altitudes of 2400–2800 m above sea level, in densely populated grey marmot settlements. The epizooty was registered in most of the southern macro-slope of Sailugem ridge, throughout 100 km and along the whole Karalakhtu ridge – throughout 30 km. The epizooty area, confirmed by plague agent isolation, amounted to 1207 km2 (45.2 % of the examined territory).

Aim - аnalysis and evaluation of efficiency of anti-epidemic, preventive actions for decrease of plague infection risk for the population and prevention of this illness export outside the Republic Altai limits. Analysis was performed by the data of practical and research Establishments of Rospotrebnadzor. Due to occurrence of three epidemic plague foci in local population in Gorno-Altai natural focus where the infection source was an Altai marmot, the complex of organizational, anti-epidemic, preventive actions was performed for its localization and liquidation and also minimization of risk of anthropogenous plague distribution in Republic Altai and its exportation from the endemic region. Interaction of the Services and Departments in realization of organizational, anti-epidemic, preventive actions in Kosh-Agach district created the necessary conditions for localization, liquidation of the epidemic plague foci in the shortest terms, prevented the illness distribution by the anthropogenous way and its exportation outside the limits of the enzootic territory.

Objective – to study the current epidemiological risks at plague enzootic frontier territory of the Bayan-Ulgy aimag of Mongolia. Materials and methods. Epidemiological analysis was performed according to the reporting documentation of the National Centre of Zoonotic Infections in Mongolia, results of anonymous questioning of 179 residents of the Bayan-Ulgy aimag of Mongolia, materials of the Department of Health of the Bayan-Ulgy aimag, the Aimag Centre of Zoonotic Infections and the Administration of the Aimag Governor. Results and discussion. Plague was first registered in the Bayan-Ulgy aimag in 1989. The total of 9 patients with plague and 4 lethal outcomes were revealed. In all cases marmots were an infection source, the infection occurred in the process of cutting the carcasses. The majority of the plague patients had bubonic form of plague. All patients were men aged 13 to 34 years. Public inquiry showed that 21,8 % of population considered meat of marmots as a delicacy, 54 % – hunted for the animals, 25,7 % – consumed uncooked organs of marmots as a folk remedy, 19,5 % – participated in cutting of marmot carcasses. Results of the inquiry indicated that a marmot was an object of active hunting for local population. Analysis of epizootic activity of the transboundary Sailugem natural plague focus, modern social and economic conditions in the Bayan-Ulgy aimag has showed that in this territory epidemic risks have shaped and act at present. They can be divided into two groups: epidemic risks capable to cause human sporadic plague cases and epidemic risks leading to anthropozoonotic plague dissemination among the population and exportation of Yersinia pestis beyond the limits of enzootic territories. Effective interaction of anti-epidemic Institutions of Mongolia and Russia and also the Agencies and Institutions of the executive power of all levels permits to counteract these risks.

Objective of the study is to comprehensively evaluate and forecast the development of epidemic process in case of anthrax in Altai Territory. Materials and methods. The data on stationary hazardous as regards anthrax areas (SHA) were obtained while analyzing cadastres of SHA in Altai Territory, as well as the reference book “Cadastre of stationary hazardous as regards anthrax areas in the Russian Federation”. Statistical and report forms from the institutions of the Rospotrebnadzor and Federal Service for Veterinary and Phytosanitary Surveillance in Altai Territory, and from Altai Plague Control Station were used for retrospective analysis of anthrax morbidity rates in Altai Territory over the period of 1953–2015. Laboratory investigations of field and clinical samples were carried out in compliance with Methodological Regulations 4.2.2413-08. Results and conclusions. Anthrax remains topical issue for Altai Territory as there are 1262 stationary hazardous areas situated in here, as well as registered animal and human infections. The density of such areas in Altai Territory is 7.5 times higher than across Siberia. Factors for the SHA formation and their sustainability are soilclimatic aspects of the region. The majority of hazardous areas are found in steppe and forest-steppe zones, predominantly along the cattle-driving paths. In Altai Territory, between 1953 and 2015, out of 1262 registered areas, 314 ones manifested epidemiological activity, including 246 new ones. Human infections were reported in 36 districts (59.1 %), while in 21 (34.4 %) – morbidity rates exceeded the territorial average. Cumulative dynamics of anthrax morbidity as regards livestock in Altai Territory in 1953–2015 showed downward trends. Complex evaluation of the situation and forecast of epidemic process development, employing composite index – epizootiological index and zoning of the territory according to the risk of epidemic complications – allows for the improvement of managerial decisions with the view to adequate anti-epidemic measures.

Objective of the study is to substantiate performance, assess the conditions, and analyze the results of activities on non-specific plague prophylaxis in the epizootic territory. Materials and methods. Utilized were archival data and operational reports of Altai Plague Control Station, Irkutsk RAPI, RusRAPI “Microbe”, Center of Hygiene and Epidemiology in the Republic of Altai, and Rospotrebnadzor Administration in the Republic of Altai, as well as literature sources. Spatial analysis was carried out using GIS-technologies. Results and conclusions. Concerted and coordinated activities of the Rospotrebnadzor institutions, medical and veterinary institutions, local executive authorities have allowed for complex prophylactic and anti-epidemic measures on prevention of plague dissemination and transmission in the territory of the Republic of Altai in 2016. Demonstrated has been the necessity to expand the scope and scale of operations and scientific research in the focus, deploying advanced toolkit of methods and means.

Objective of the study is to sum-up the results of prophylactic (anti-epidemic) measures associated with elimination of epidemic focus in Kosh-Agach Region of the Republic of Altai in 2016. Materials and methods. Utilized were the data of reporting and source documentation from Altai Plague Control Station, Rospotrebnadzor Administration in the Republic of Altai, RusRAPI “Microbe”, and Irkutsk RAPI. Results and conclusions. It is pointed out that carried out in 2016 complex of organizational, anti-epidemic, and sanitary-prophylactic activities against plague is the importnant stage of rehabilitation of Gorno-Altai high-mountain natural plague focus, the final goal of which is maximally possible decrement of risks of primary human infection with plague, and in case of occurrence of such – performing of prompt response measures on localization and elimination of epidemic focus. It has been substantiated that for epidemic risk minimization in 2017 it is necessary to continue prophylactic vaccination, desinsection and deratization in the areas of predictive epizootic situation aggravation, which is contained in “Complex Action Plan of the Rospotrebnadzor Institutions for Sanitation and Rehabilitation of Gorno-Altai high-mountain natural plague focus in Kosh-Agach Region of the Altai Republic in 2017”. It is also necessary to provide for implementation of the Program on lowering risks of importation from cross-border Sailyugemsky natural focus and spread of plague in the territory of the Russian Federation, within the frames of RF Government Order No 1864-p, dated 05.09.2016.

The data, describing epizootical and epidemical activity of the Gorno-Altai natural plague focus in 2012 - 2016 are shown. The wide dissemination of the major Yersinia pestis subtype in Marmota baibacina’s settlements led to the focus epidemical potential growth and became the reason of epidemical complications in Kosh-Agatch district of the Republic of Altai in 2012 - 2016.

Laboratory diagnostics of plague was carried out in compliance with valid operational guidelines and regulations. But its peculiarity consisted in the performance of diagnostic investigations secondary to antimicrobial therapy with application of preparations characterized by the expressed activity towards gram-negative microorganisms, including the agent of plague (ceftriaxone, ciprolet, and amikacin). The studies revealed that under antibiotic treatment during the early phase of infection the most effective method for the laboratory plague diagnostics was PCR. Based on the results of the assay it was possible to establish not only provisional, but also the final diagnosis in a patient. Obtained was genetic characteristics of the strains isolated from the patient and the marmot, withdrawn at the patient’s place, using techniques of molecular-genetic analysis, in particular PCR, multilocus VNTR, and multilocus and genome-wide sequencing. Thereupon the strains were attributed to antique biovar of the main subspecies of plague agent. In addition, close relation to Y. pestis of the main subspecies isolated in the same focus in 2012 and to the strains from Mongolian Altai and Tuvinian mountain focus was determined based on phylogenetic analysis of the isolates.

For the first time ever since the discovery of the Gorno-Altaisk high-mountain natural focus in 1961, registered has been a case of human plague infection. It occurred in the consequence of the grey marmot cutting that was caught in the territory of one of the persistent epizootic regions of the natural plague focus. The outbreak was localized and eliminated following complex anti-epidemic measures, including medical treatment of the patient; identification, isolation and management of the contact persons, both to the patient and marmot; withdrawal and disposal of marmots’ carcasses, obtained during unauthorized commercial hunting; specific and non-specific prophylaxis of the disease. Also for the first time ever received have been the evidences of concurrent circulation of the strains, subspecies Y. pestis ssp pestis and Y. pestis ssp. altaica in the regions of cohabitation of Pallas’ pika (Ochotona pallasi), Siberian souslik (Citellus undulatus), and grey marmot. Specified is the necessity to reconsider the tactics of epizootiological plague monitoring in enzootic territories where circulation of various Y. pestis subspecies is registered.

Performed is a complex microbiological, molecular-genetic and mass-spectrometric identification of Yersinia pestis main ssp. strain, which was isolated for the first time in the history of surveillance over the Altai mountain natural plague focus in June, 2012. Determined is its high universal virulence. Plasmid screening, multi-locus VNTR- and mass-spectrometric analyses have revealed the strain to be more closely related to the plague agent variant, circulating in the territory of the natural focus Khuukh-Serkh-Munkh-Khairkhan, Bayan-Ul’giisk aimak, Mongolia.