Mongolian Part of the Trans-Boundary Sailugem Natural Plague Focus in 2017. Communication 2. Modern Epidemiological Risks

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

A Case of Human Plague in Kosh-Agach Region of the Republic of Altai in 2015. Communication 2. Microbiological and Molecular-Genetic Characteristics of the Isolated Strains

Objective of the study was a complex pheno- and genotypic investigation of Yersinia pestis I-3595 and Y. pestis I-3596 strains, isolated from marmots that were the source of human infection in 2015. Materials and methods. A comprehensive microbiological, molecular-genetic and mass-spectrometric studying of Y. pestis ssp. pestis strains, isolated from two grey marmots that became a cause of the plague case in Gorno-Altai high-mountain focus in 2015, was performed using up-to-date methods. Results and conclusions. It was established that the studied Y. pestis strains belonged to the main subspecies. Results of plasmid screening, multilocus VNTR-and mass-spectrometric analyses showed that those strains were closely related to Y. pestis variant detected in the focus in 2012 and in 2014, and circulating in Northwest Mongolia and Tuva natural focus

Mongolian Part of the Transboundary Sailugem Natural Plague Focus in 2017. Communication 1. Epizootic condition

Objective – estimation of current epizootic condition of Mongolian part of transboundary Sailugem natural plague focus. Materials and methods. Epizootiological survey was performed for the area of 2335 km2, 277 mammals and 516 ectoparasites were investigated for plague. Results and conclusions. Eight Yersinia pestis subsp. pestis strains were isolated, including 7 strains – from grey marmots (6 – from the remains of meals of predatory birds, 1 from a corpse) and 1 – from long-tailed souslik (corpse). Y. pestis DNA was detected in 52 objects. Serological samples showed 40 positive results. Epizootic manifestations, confirmed by isolation of Y. pestis cultures, detection of plague microbe DNA, and positive serological results, were observed across the area of 1611 km2 covering 69 % of the inspected territory. Epizootic results indicated high infection rate of mass mammal species and first of all grey marmots. The data demonstrated that the extended plague epizooty caused by Y. pestis of the main subspecies occurred in the inspected territory in the carrier settlements. For the first time the circulation of Y. pestis subsp. pestis was registered in the Mongolian part of the transboundary Sailugem focus

Epidemiological Situation on Natural Focal Infectious Diseases of Bacterial and Viral Etiology in 2012 in the Territory of Siberia and Far East, and Prognosis for 2013

Analyzed is the incidence rate as regards natural focal infections of bacterial and viral etiology. Displayed is the data on the performed laboratory diagnostics of these infections in the territory of Siberia and Far East in 2012 and forecast of the epidemiological situation development in 2013. Analysis is carried out based on the data received by the Reference Center for surveillance over natural focal infections at the Irkutsk Research Anti-Plague Institute, from Rospotrebnadzor Institutions of Siberian, Far-Eastern and Ural Federal districts, as well as reviews and prognoses on the current state of natural foci of infections available from Altay, Tuva, Chita, Khabarovsk and Primorsk plague control stations

A Case of Human Infection with Plague in the Kosh-Agach Region of the Republic of Altai in 2015. Communication 1. Clinical-Epidemiological and Epizootiological Aspects

Objective of the study is to characterize the case of human plague in the territory of Gorno-Altaisk high-mountain natural focus in 2015 and to analyze the initiated measures, associated with localization and elimination of epidemic focus. Materials and methods. Utilized are the data contained in reporting and source (primary) documentation of the FGHI “Altai Plague Control Station”, records of the Rospotrebnadzor Administration in the Republic of Altai, and information collected by the FGHI “Irkutsk Research Anti-Plague Institute”. Results and conclusions. Human infection occurred as a result of gray marmot dressing, which was caught in the Elangash River-Valley, against the background of unfavorable epizootic situation, caused by proliferation of the plague agent of main subspecie in the territory of the focus. Clinical material investigations, performed by means of bacteriological and molecular-genetic methods, showed negative findings. Applying serological method within the system of indirect hemagglutination test (IHAT)/antigen neutralization test (ANT), in blood sera, obtained at the time of hospitalization, low-titred specific antibodies to plague microbe (recognized as post-vaccinal ones) were detected. In blood serum sample, obtained 7 days later, identified were high-titer antibodies, which allowed for confirmation of clinical diagnosis - “bubonic plague”. Due to efficient cooperation between Rospotrebnadzor institutions and medical facilities, as well as municipal authorities it was possible to avoid further development of anthropogenic transmission of plague; to localize and eliminate epidemic outbreak of this dangerous infectious disease in Kosh-Agach Region of the Republic of Altai in the shortest possible time

Adjuvant properties of chitosan derivatives administered to mice with anti-rabies vaccine

Searching for a preparation that would meet all the requirements for modern adjuvants remains a matter of critical importance for specific immunoprophylaxis. Much information is available now on chitosan positive effect, including its effect on the immune response. The article provides results of the preclinical tests for different affordable chitosan-based products. For the test purposes, we took the following three products manufactured by LLC Bioprogress (Shchelkovo, Russia): water-soluble chitosan (succinate) – 2% solution edible chitosan (water-soluble) – 2% solution; edible chitosan (acid-soluble) – 2% solution, as well as antirabies vaccine RABIKOV manufactured by Shchelkovo Biocombinat (Russia). Immunogenic properties of chitosan-based products were tested in 85–100-day-old female white laboratory mice weighing 21–35 g. The animals were divided into 37 groups (6 mice in each group). Chitosan-based products were administered subcutaneously or intramuscularly, either together with the anti-rabies vaccine or without it. Animals from the control groups received either saline solution or the vaccine only. There was also a group of intact animals. The experiment demonstrated that the water-soluble chitosan (succinate) administered subcutaneously, acid-soluble edible chitosan (at a concentration of 1:64 and more), and water-soluble edible chitosan (at a concentration of 1:108) administered subcutaneously and intramuscularly increase the level of post-vaccination anti-rabies antibodies. Thus, the tested chitosan-based products do not have any negative impact on the laboratory animals and have immunogenic properties

MLVA25-Typed Yersinia pestis ssp. central asiatica biovar altaica Genotype Structure in Gorno-Altai Mountain Natural Plague Focus

The aim of the work was to study the genetic diversity and spatial-temporal genotype structure of Yersinia pestis subspecies central asiatica biovar altaica in the Gorno-Altai natural plague focus, using MLVA25-typing.Materials and methods. MLVA25-typing of 330 strains of Y. pestis ssp. central asiatica bv. altaica, isolated in the Gorno-Altai mountain natural plague focus during 1961–2015 was carried out. The phylogenetic tree was constructed with the help of UPGMA and MST algorithms.Results and discussion. The analyzed strains have been differentiated into 34 MLVA types based on cluster analysis. The formed major groups of strains show pronounced spatial confinedness. Three chorological groupings of the plague agent with peculiar genotype characteristics have been identified. Each of the groupings is circulating among the main carrier (Ochotona pallasi) population and within the limits of the similarly-named mesofocus, respectively (Ulandryksky, Tarkhatynsky and Kuraisky). MLVA25 structure of Y. pestis in Ulandryksky and Kuraisky mezofoci show stability over time; there are no significant changes from the time of their first detection in 1961 and 1999, respectively. The dramatic changes in MLVA25 structure are observed in Tarkhatynsky mesofocus, which is known from 1972. Mass expanding of the MLVA25 types which were very rare before took place there from the beginning of 1990-s, along with elimination of the types absolutely dominant up to 1980s. Most likely the changing of dominating genotypes is attributable to the bottleneck effect, arising from the sharp decline of the focal epizootic activity in the mid 1980s

<i>Yersinia pestis</i> ssp. <i>pestis</i> Spatial MLVA25 Genotypic Structure in the Transboundary Saylyugem Natural Plague Focus

Advanced molecular-genetic methods for the diagnosis and typing of Yersinia pestis ssp. pestis in the field and clinical material are used for epidemiological surveillance of plague in the Saylyugem natural focus. The aim of the work was to study the spatial genotypic structure of Y. pestis ssp. pestis in the transboundary Saylyugem natural plague focus using MLVA25 typing. Materials and methods. The MLVA25 typing of 160 strains of Y. pestis ssp. Pestis isolated in the Saylyugem natural plague focus in 2012–2021 was carried out. Phylogenetic tree construction was performed with the help of UPGMA and MST methods. Results and discussion. The Y. pestis ssp. pestis strains isolated from the Saylyugem natural plague focus were differentiated into 15 MLVA types by the 25 VNTR loci cluster analysis. The studied strains form a homogeneous complex of MLVA25 types without marked geographical distribution across seven spatial groups. The analysis of the frequency of occurrence of the tandem repeats number for three variable loci of Y. pestis ssp. pestis strains shows the significant differences between the samples from the Mongolian and Russian parts of the Saylyugem natural plague focus. The most pronounced differences in spatial genotypic structure are traced through the yp4280ms62 locus

Molecular-Genetic Characteristics of Yersinia pestis Strains Isolated in the Mongolian Territory of Transboundary Sailyugem Natural Plague Focus

Objective: investigation of phylogenetic origin and affinity of Yersinia pestis strains isolated from field material collected during the epizootiologic survey of the Mongolian part of trans-boundary Sailyugem natural plague focus. Materials and methods: MLVA25-typing of 81 Y. pestis strains, including 55 isolates from the Mongolian part of transboundary Sailyugem natural plague focus, collected in 2017-2018 was carried out. The plague agent strains isolated in different years in the natural foci of Northwest Mongolia and Southern Siberia were used as comparison group. Whole genome sequencing was performed for 21 Y. pestis strains subspecies pestis isolated in Mongolia in 2018 and 1988-1990 and in Gorny Altai of the Russian Federation in 2012-2016. SNP-typing was conducted on the basis of whole genomes of Y. pestis strains identified in the current research and also genomes from GenBank international database. Search of single nucleotide polymorphisms in Y. pestis genomes was carried out in two ways: by means of snippy v. 4.3.5 software and using mummer v. 3.1 package and a set of the author’s scripts. Phylogenetic reconstruction was conducted with the help of RAxML method. Results and discussion: Results of MLVA25 typing of Y. pestis subsp. pestis demonstrated that the strains isolated in Mongolian and Russian parts of the Sailyugem and Khuukh-Serkh-Munkh-Khairkhan natural foci belong to one common cluster. SNP-typing placed the studied isolates from the Mongolian and Russian territories into 4. ANT phylogenetic line with high level of reliability which testifies to the genetic similarity of the specified pathogen groups. The data of MLVA- and SNP-typing showed insignificant variability of the plague agent in the territory of the Mongolian part of trans-boundary Sailyugem natural plague focus. On the basis of the conducted research and results of epizootiological monitoring of Russia and Mongolia border territories it is possible to draw a conclusion on gradual wide penetration of Y. pestis subsp. pestis mainly into grey marmot settlements in Southeast Altai from Northwest Mongolia

Gorno-Altai Natural Plague Focus Epizootical and Epidemical Activity in 2012 - 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