The review is based on the results of studying arctic rabies in the tundra and taiga forests of northeastern Russia between 1855 and 2024. The aim of the work was to trace the evolution of scientific knowledge on rabies in Yakutia, to identify the most significant results and prospective areas of research drawing on data accumulated over the observation period. The change of paradigms and priorities at different stages of the study is noted. The spatial-temporal analysis of the rabies spread was carried out through comparing two periods – from the early 21st century and for previous years. Mapping is based on the Natural Earth electronic map in the QGIS 3.2.1 program. Statistical analysis of the dynamics of rabies incidence by years is performed in Rstudio software. Published data on rabies in various animal species are summarized in the table by periods with different diagnostic capabilities. Sporadic human rabies cases in Yakutia (n=6) were identified in 1926 and 1974–1975. Early reports of high rabies incidence in lemmings and detection of the “classical” rabies virus in Yakutia are critically analyzed from the standpoint of modern knowledge. All deposited in GenBank nucleotide sequences of rabies virus genes from Yakutia (n=28) belonged to the arctic genetic line. The relevance of genomic epidemiological surveillance in investigating outbreaks in the central and southern regions of Yakutia is substantiated. The data presented in the review are proposed to be used for planning scientific research and forecasting rabies epizootics in the Arctic.

The results of epizootiological and epidemiological monitoring of hemorrhagic fever with renal syndrome (HFRS) in the Russian Federation in 2024 and a forecast for 2025 are presented in the paper. In 2024, 3,396 cases of HFRS were registered in the Russian Federation (3.32 per 100 thousand population) – a decrease in the incidence of HFRS by 32.3 % as compared to previous year’s data was noted. The age structure of the patients was dominated by people aged 30–59 years (66.3 %, with some exceptions); 161 cases of the disease were observed among children under 17 years of age. The share of the male population was 72 %. The mortality rate was recorded at the level of 0.29 % – 10 lethal outcomes. In 2025, it is predicted that the tense epidemiological situation on HFRS will be retained in the constituent entities of the Volga and Central Federal Districts. Conditions for the occurrence of sporadic cases of HFRS will remain in the Northwestern, Ural, and Far Eastern Districts. Sporadic cases of the disease are possible in certain territories of the entities of the Southern, North Caucasian and Siberian Federal Districts. Proposals have been formulated to minimize possible epidemiological complications in the country for the forecasted period and the near future. The main areas of scientific developments aimed at improving the quality of epidemiological surveillance of HFRS, currently carried out using highly productive advanced technologies for data processing, analysis and visualization, are considered.

The analytical review presents information on current situation on brucellosis in the Russian Federation. According to long-term data, on average, more than 400 cases of brucellosis among population are registered in Russia annually; incidence rate per 100 thousand population is 0.29. More than 70 % of brucellosis cases were detected in the territory with active cattle breeding in the south of the European part of the country. Since 2022, there has been an increase in the number of human brucellosis cases in regions with developed livestock farming in territories enzootic for brucellosis (mainly the Republic of Dagestan) and in previously relatively safe entities (Bryansk, Smolensk Regions, the Republic of Tatarstan, Penza Region, Krasnoyarsk Territory). In 2024, 530 cases of brucellosis were registered (0.36 per 100 thousand population), which exceeds the average long-term indicators by 27, 4 %. The emergence of group epidemic outbreaks among professional contingent at public sector farms and “family” epidemiological foci on private subsidiary farms can be considered as new threats in terms of brucellosis. Taking into account the development trends of the situation on brucellosis, in 2025, the incidence rate is predicted to be 30–40 % higher than average long-term level, which may amount to 480–530 new cases (0,32–0,36 per 100 thousand population).

The aim of the review was to characterize the epidemiological situation on Ixodidae tick-borne borreliosis (ITBB) in the constituent entities of the Russian Federation in 2024, to forecast the development of the ITBB epidemic process in 2025 based on the analysis of its trends over the period of 2010–2024 with the exception of 2020–2021 – the period of the COVID-19 pandemic. An assessment of the epidemic potential of ITBB in Russia and other countries, where there is an increase in the activity of foci and an expansion of the range of pathogens, is provided. An analysis of the incidence of ITBB in the Russian Federation in 2024 has been conducted in comparison with the average long-term indicators for 2010–2019. In 2024, a total of 7 365 cases of ITBB were registered in the Russian Federation. The morbidity rate of ITBB in 2024 was 4.84 per 10 000 population, which is statistically significantly lower than the similar figure for 2023 (6.25 per 100,000 population), however it lies within the range of average long-term values between 2010 and 2019 (4.99 per 100,000 population). In 2024, the indicator in the majority of the federal districts (Northwestern Federal District, Volga Federal District, Ural Federal District, Siberian Federal District, and Far Eastern Federal District) either did not reach or remained within the average long-term incidence rates of ITBB observed in 2010–2019. In contrast, the Central, Southern, and North-Caucasian Federal Districts reported ITBB incidence rates that were above the mentioned long-term averages. The epidemiological situation regarding ITBB in the Russian Federation remains tense. Based on projected ITBB incidence rates, its decrease is expected in the Central, Northwestern, and Volga Federal Districts in 2025. Effective control of the ITBB epidemic situation is possible provided that the volume of preventive measures is maintained, and zoological-entomological monitoring of the activity and structure of natural foci is strengthened.

Epizootiological and epidemiological situation on anthrax in the world in 2024 has been reviewed, dynamics of anthrax incidence in the period of 2015–2024 and the forecast of anthrax incidence in 2025 in the Russian Federation are presented. In 2024, one outbreak of anthrax was detected in Russia, in a constituent entity of the Central Federal District, with the disease affecting two farm animals and three people. Compared to 2023, when seven outbreaks were registered in five regions, in 2024 Russia saw a decrease in the number of infection cases by 12 – among farm animals and 16 – among people. Anthrax manifested in four neighboring countries, with the most unfavorable situation occurring in Kazakhstan and Kyrgyzstan. Outbreaks of infection among farm and wild animals were recorded on all continents, with the largest number of cases in Africa and Asia. Cases of anthrax in humans have been identified in a number of countries in Africa, Asia, North and South America and Europe and were caused by contact with sick farm animals during forced slaughter, butchering of carcasses and meat, and eating meat from sick and dead animals. Also, in one of the Asian countries (Pakistan), a bioterrorism act was implemented through distributing letters containing anthrax spores, which did not lead to human infection. The incidence of anthrax in animals and humans in 2025 in the Russian Federation will depend on the scale of animal registration and vaccination measures, the completeness of inclusion of population at risk in immunization scheme and implementation of preventive vaccination plans. With strict adherence to anti-anthrax monitoring and surveillance measures, the incidence of anthrax in Russia will not exceed the level of isolated cases.

The aim of the work was to create an analytical model of a test disease X pandemic that requires a priority approach to ensuring biological safety, using COVID-19 and influenza as an example. The created pandemic model consists of 2 elements: the pandemic phenomenon itself using COVID-19 as a case study and the post-pandemic period using the Spanish flu as an example. The formalized structure, signs, parameters, properties and negative consequences of the COVID-19 pandemic as a phenomenon with an extraordinary scale of epidemic spread, socio-economic and other critical consequences that disorganize society, comparable with threats to national and international security, the readiness for which is a part of ensuring biological safety in a broad format, have been determined using the epidemiological method, the law of large numbers (LLN in probability theory), and the global application of digital and genomic technologies. An in-depth study of the COVID-19 pandemic has revealed the value of a certain structure of the clinical and epidemiological content of the epidemic phase of the pandemic, which determined the high quantitative parameters of spread and mortality. A 10-fold range of change in the key criterion, both upward and downward, has been established, which is incompatible with the emergence and existence of a pandemic as a phenomenon. The proof of the effectiveness, efficiency, scientific and practical significance of the COVID-19-based disease X pandemic model is the full implementation of the epidemiological forecast of COVID-19 pandemic duration in 2024 that we have developed for all its elements and parameters. The imitation of the post-pandemic period of disease X is represented by data on the circulation of the H1N1 influenza virus for more than 100 years, seasonal outbreaks and epidemics between 1920 and 1957, four moderate pandemics relative to the “Spanish flu” after 1957, and the production of particularly pathogenic potentially epidemic variants of the influenza virus. In general, the model is proposed to be used to monitor and assess preparedness for future pandemics in the format of biological disasters when forming state policy in the field of biological safety, as well as to prevent the occurrence of emergencies within the framework of the implementation of the International Health Regulations (2005).

The aim of the work was to determine the rate of infection by various Leptospira genomospecies of wild and synanthropic small mammals collected on the territory of St. Petersburg. Materials and methods. The capture of wild and synanthropic small mammals was carried out using Gero-type traps in the Kurortny and Kirovsky districts of St. Petersburg between September and October, 2021. The study of samples for the presence of Leptospira spp. DNA was performed applying PCR with primers selected for the lipL32 gene fragment. Genotyping of samples was conducted using primers for fragments of the secY and rpoB genes. Results and discussion. DNA of pathogenic Leptospira was detected in 8 samples, which amounted to (4.2±1.5) % of the total number of samples (190). The infection rate of gray rats collected in the Kirovsky district was (11.1±5.2) % (4/36). The infection rate of wild rodents collected in the Kurortny district was (3.7±2.6) % (2/54) for yellow-throated mice, and (2.0±1.4) % for bank voles (2/100). Based on the results of analysis of sequences obtained, the circulation of two pathogenic Leptospira species, L. interrogans and L. borgpetersenii, has been established. Our results confirm the circulation of Leptospira both among wild and synanthropic small mammals. The phylogenetic species of pathogenic Leptospira identified in our study are typical and associated with the studied rodents. In order to prevent the disease in humans, it is necessary to continue research aimed at identifying the circulation of pathogens in populations of wild and synanthropic small mammals. Deratization and activities aimed at educating residents of St. Petersburg about protection and prevention measures are required.

The aim of the work was to determine the relationship between the existing weather and climatic conditions and the inter-epizootic period in the Central-Caucasian high mountain natural focus of plague. Objectives: a) to identify weather and climate indicators potentially associated with the activity of a natural plague focus – optimal and pessimal values of these indicators for recording plague epizootics; b) to determine whether there are differences in the number of pessimal factors for recording epizootics during epizootic and inter-epizootic periods. Materials and methods. Data on the epizootic activity of the Central-Caucasian high mountain natural plague focus from 1987 to 2021 were studied. Information on the minimum, maximum and average air temperatures by months, the amount of precipitation by months, the average humidity, the value of atmospheric pressure were analyzed: a total of 72 weather indicators (Shadzhatmaz weather station). Statistical processing was carried out using a nonparametric sequential statistical recognition procedure, Spearman correlation analysis, and the Mann–Wilcoxon–Whitney test. To calculate statistics, the Python library sсipy. stat was used. Results and discussion. During high epizootic activity, the values of weather indicators were mainly in favorable ranges. After 2008, the values of weather indicators shifted mainly to unfavorable ranges. Values of weather indicators that are non-informative also tended to be beyond the limits of tolerance. Climatic changes adversely affect the epizootic activity of the focus. At the same time, the ecosystem of the focus is gradually adapting to climate change. It can be expected that the epizootic activity of the focus will be recorded sporadically, given some improvement in the weather conditions.

The aim of the work was to compare the survival ability of virulent strains of tularemia microbe, mediasiatica and holarctica subspecies, endemic to Russia, in the aquatic environment and in the animal organism. Materials and methods. 11 virulent strains of various subspecies deposited in the State collection “SCPM-Obolensk” were used in the work. To assess the survival rate, bacterial cells of the studied strains at a concentration of 5·10⁶ CFU/ml were incubated for 35 days in autoclaved tap water. The viability of Francisella tularensis bacterial cells was determined immediately before the experiment and then weekly by seeding on agar plates. To compare the holarctica and mediasiatica strains by in vivo survival ability during co-infection, the strain mixture was passaged three times through mice, the ratio of colonies of each strain in the spleen being calculated at each passage. Colony differentiation was performed by assessing the length of the Ft-M20 VNTR locus using PCR and subsequent gel electrophoresis. Results and discussion. Subsp. mediasiatica shows significantly lower ability to survive in water compared to subsp. holarctica. At the same time, analysis of the results of seeding after co-infection of mice with strains belonging to the two subspecies indicates that subsp. mediasiatica reproduces in the host organism more effectively than subsp. holarctica.

The aim of the study was to determine the phylogeographic and phenotypic characteristics of the Burkholderia mallei that caused an outbreak of equine glanders in the Trans-Baikal Territory in 2023. Materials and methods. The B. mallei culture was isolated from section material according to Methodological Regulations 4.2.3744-22. Phenotypic characteristics were investigated bacteriologically and using the VITEK®2 GN. Analysis of the B. mallei genomes from public databases was performed using the PubMLST, NGphylogeny, and iTOL v6 resources. Results and discussion. Strains of B. mallei 16050 and 15747, isolated from the horse affected by glanders, identified using PCR, differed in morphological features, but had identical atypical biochemical profiles which lead to misidentification by VITEK®2 GN system as Sphingomonas paucimobillis. Shotgun analysis of the whole genome sequences confirmed the identity of those strains; a subsequent study was performed using a higher quality sequence of B. mallei strain 16050. Phylogenetic analysis based on the results of cgMLST showed the inclusion of the strain B. mallei 16050 in a separate cluster, grouped near the cluster of 5 strains, three of which (B-120, Ц-5, Ц-4) are reliably of Mongolian origin, the other two strains (Z-12 and 10230) have high similarity to Mongolian strains which is demonstrated in the current work. It has been revealed that 87 loci of the strain 16050 have new alleles, which can serve as a marker in genomic surveillance and investigation of imported cases of glanders. The data obtained allow us to assume with a high degree of probability that the outbreak of equine glanders in Chita in 2023 was caused by a strain of Mongolian origin.

The territory of South-East Asia, including Vietnam, is one of the disadvantaged in relation to leptospirosis areas. According to studies, 10 % of the Vietnamese population is infected with Leptospira, but at the same time, information about circulating Leptospira species, the main carriers of infection in various regions of Vietnam, is very limited. The aim of the work was to investigate the circulation of leptospirosis pathogens in various provinces of Vietnam, for which a study of suspensions of small mammalian organs was conducted, and the level of the immune stratum of the population living in the surveyed territories was determined. Materials and methods. The work was carried out on the base of the mobile laboratory for monitoring and diagnostics, as well as the Laboratory of Toxicology and Tropical Diseases of the Institute of Tropical Medicine. Molecular-genetic methods (PCR and sequencing) were used to study 2,790 samples of suspensions of small mammalian organs collected in 14 provinces located in the northern, central and southern parts of the country between 2019 and 2024. Additionally, 576 sera from conditionally healthy people, obtained in 5 northern provinces of Vietnam, were studied by ELISA to assess the intensity of immunity to Leptospira. Markers of pathogenic Leptospira were detected in 282 samples from 20 different species of small mammals using PCR, while positive results were obtained in samples from all the provinces studied. 76 positive samples were sequenced, as a result of which appurtenance to the species Leptospira interrogans, Leptospira borgpetersenii, Leptospira mayottensis was established. Specific IgG class antibodies to Leptospira were detected in 8.0 % of the cases. A risk group has been identified – people employed in agriculture. The results obtained show the ubiquitous spread of leptospirosis pathogens in Vietnam. A promising field of research is the zoning of the country’s territories according to the intensity of epidemic manifestations of leptospirosis, the determination of the species composition of circulating Leptospira and the main carriers among mammals, taking into account the landscape, geographical and socio-economic factors.

The Volga-Ural sandy natural plague focus is a transboundary one. Its greater part (66,036 km² ) is located on the territory of two regions of the Republic of Kazakhstan, the smaller part (8,625 km² ) is on the territory of the Russian Federation. The aim of the work was to conduct epizootiological differentiation of the southern part of the Volga-Ural sandy plague focus. Materials and methods. Retrospective data from epizootiological survey of the focus conducted by the Astrakhan (Russian Federation) and Atyrau (Republic of Kazakhstan) Plague Control Stations were used. The coordinates (latitude and longitude) of 865 sites where the plague agent was detected over the period of 1936–2005 were determined. Using the method of circular extrapolation of each point with plague manifestations, annual maps of epizootic areas were drawn. By successive overlay of the created electronic maps, the dislocation of the activity cores of the natural focus and the zones of short-term registration of the epizootic process were revealed, and their quantitative characteristics were determined. Results and discussion. Identification of a detailed configuration of the most active zones of manifestation of the epizootic process has significant prognostic value in the search for plague-infected animals, especially during inter-epizootic periods. The cartographic model of differentiation of the focal territory by activity and duration of epizootics is intended for substantiated planning of epidemiological surveillance measures, prevention and further study of the issues of plague enzootics. The obtained data can be used for epidemiological zoning of the territory as regards plague.

The widespread distribution of natural foci of tularemia on the territory of the Russian Federation necessitates the creation of new and improvement of existing methods of immunodiagnostics of the pathogen. To date, the search for Francisella tularensis antigens that could provide high sensitivity and specificity of diagnostic test systems developed on their basis remains an urgent task. At the same time, great hopes are placed on the surface structures of the cells of tularemia microbe (LPS and outer membrane proteins) and secreted stress proteins. The aim of the work was to evaluate the diagnostic value of rabbit polyclonal antibodies to complex antigens and secreted stress proteins of tularemia microbe. Materials and methods. The work used a vaccine strain, its acapsular derivative, 6 virulent strains of F. tularensis of different subspecies and biovars, as well as 10 strains of heterologous microorganisms. The diagnostic significance of the obtained sera was assessed using immunochemical and serological methods: enzyme immunoassay, immunoblotting, microagglutination reaction and indirect hemagglutination. Pure cultures of microorganisms and suspensions of organs from laboratory animals vaccinated with F. tularensis 15NIIEG and infected with F. tularensis 503/840 were used as samples. Results and discussion. Polyclonal antibodies to outer membrane antigens and secreted stress proteins of F. tularensis have been obtained. Their epitope orientation was determined using immunoblotting. The ability of the obtained polyclonal antibodies to enter into serological reactions with specific antigens of F. tularensis of different subspecies in immunological tests has been demonstrated. It has been found that these antibodies can be used to detect the pathogen in organ suspensions of vaccinated and infected laboratory animals. We have established that antibodies to complex antigens of F. tularensis, which in addition to the protein component include the carbohydrate component of the tularemia microbe cells, have the greatest diagnostic significance. Polyclonal antibodies to individual secreted stress proteins (Bfr and GroEL/GroES) are specific, but do not allow identifying the pathogen at its low concentration in the sample, which may be due to different intensities of expression of these antigens during the life of the microorganism.

Work with particularly dangerous pathogens is associated with occupational risks (the likelihood of manmade accidents, laboratory infection of workers) and requires the acquisition and improvement of knowledge, skills, and abilities in the safe performance of manipulations. One of the basic components of the biosafety system in training specialists is a set of regulated preventive (anti-epidemic) measures to reduce biorisk and promptly detect infection: medical examinations, vaccination and observation (upon indications), testing knowledge of biosafety rules, daily medical examination (interviewing, examination, thermometry). Gradual reduction, since 1990, in the practice hours of professional retraining of workers, from six to three months, while attaining the training objective – reliable and safe professional activity – necessitates increasing the intensity of development of skills and abilities in safe work and, accordingly, additional measures to reduce biorisk when working with pathogens for course participants who initially do not have professional skills and abilities. The aim of this study is to improve the set of preventive (anti-epidemic) measures to reduce the risk of man-made accidents and laboratory infections when training in safe work with pathogenic biological agents of groups I–II (PBA). The analysis of legislative, regulatory and methodological documents, by-laws, information and patent search in the field of ensuring biosafety of work with PBA and additional professional education has been carried out. A list of additional preventive (anti-epidemic) measures to the regulated set of measures to ensure biosafety has been proposed, training tools to reduce biorisk in practical classes have been developed: five training sets of strains of particularly dangerous bacteria and algorithms for their safe use; a set of standard operational microbiological procedures; methods of personalized assessment of professionally important qualities and individual model of safe behavior, levels of occupational health, preparedness, reliability of professional activity and risk of their decrement in a trainee.

The aim of our work was to determine genetic markers associated with attenuation (deletions in RD-18, RD-19 positions, single mutations) in natural strains of the causative agent of tularemia. Materials and methods. The work used 107 Francisella tularensis strains from the State Collection of Pathogenic Bacteria of the Russian Anti-Plague Institute “Microbe”, as well as 1077 F. tularensis genomes provided by the NCBI GenBank database. Cultivation was carried out on Petri dishes with FT-agar (State Research Center of Applied Microbiology and Biotechnology), pH 7.2; the cultures were incubated for 36–48 h at a temperature of (37±1) °С. The draft genome was assembled using the Unicycler v.0.4.7 software package. The snippy v.4.6.0 program was used to obtain a matrix of core SNPs. The dendrogram was drawn in the PhyML program using the Likelihood method with the GTR substitution model. Results and discussion. Among the studied strains of tularemia microbe, eleven erythromycin-resistant strains of F. tularensis of the phylogenetic groups B.12 B.24 and B.12 B.20 were identified, containing deletions in the RD-18 and RD-19 regions. Erythromycinresistant and erythromycin-sensitive cultures of the pathogen of the groups B.12 B.24, B.12 B.20, B.12 B.39 and B.4, B.6 B.10, B.6 B.7, respectively, were also identified, having a deletion only in the RD-18 region – 11 strains, and only in RD-19 – 8. Of the 11 cultures with deletions in both regions, in 9 cases the strains belonged to the phylogenetic group B.12 B.24 and formed a separate cluster, the remaining two – to B.12 B.20. The cluster of such strains is characterized by the presence of seven unique mutations associated with the formation of lipopolysaccharide, metabolism of aromatic compounds and reproduction in macrophages. Three additional specific mutations have been identified for the B.12 B.24 group strains. We have identified 29 strains of the tularemia pathogen (vaccine ones, their derivatives and natural ones), carrying genetic markers associated with attenuation to varying degrees.

The aim of the study was to develop an agent-based model of the epizootic process based on the analysis of the interaction between the pathogen and its hosts at the population level in order to improve methods for predicting the spread of plague. Materials and methods. An analysis of the course of plague epizootics has been carried out, the main assumptions and simplifications of the model are formulated. The structure of a multi-level tree-like system of goals has been built and their coordination with the functions that ensure the achievement of goals provided. The types of agents, their number and characteristics, the mechanism of interaction with each other and with the external environment have been determined. Results and discussion. The experience of using the simulation model to analyze and predict epizootic manifestations in natural plague foci indicates its practical value for solving problems related to risk management arising from this infection. Simulation models allow us to take into account complex interactions between various factors and assess the impact of various intervention strategies on the development of the situation. An important advantage of agentbased modeling is the ability to reproduce the heterogeneity of the host population and take into account the individual characteristics of their behavior and susceptibility to infection. Simulation is a promising tool for improving the system of epidemiological surveillance and plague control. The developed model can be used to make informed managerial decisions aimed at reducing the risk of disease in the population. Further research will be aimed at expanding the model by including additional factors (for example, climatic and social ones) and adapting it for use in specific natural plague foci. The model can be scaled and applied not only to local outbreaks of plague, but also to simulate the spread of infection in wider areas.

The aim of the work is to determine an evolutionary and phylogeographic origin of Bacillus anthracis strains that caused large-scale outbreaks of anthrax in the Central Federal District in 2023. Materials and methods. Whole genome sequencing of 13 strains of the anthrax pathogen isolated in the Ryazan and Voronezh Regions was performed. It was conducted using the Ion GeneStudio S5 Plus System (Life Technologies, USA) and DNBSEQ-G50 (MGI, China) high-throughput sequencing platforms. A whole-genome SNP analysis of 1245 Bacillus anthracis strains from 50 countries, including 304 strains from 44 constituent entities of the Russian Federation, was carried out. Results and discussion. It has been established that the anthrax strains isolated in the Central Federal District in 2023 fall under the phylogenetic branch A.Br.117, which belongs to the monophyletic clade TEA Tsiankovskii. Strains 1394, 1395 (Ryazan Region), 1402, 1404 (Voronezh Region, Paninsky District) belong to the genotype A.Br.117-2, and strains 1405–1420 (Voronezh Region, Bogucharsky District) – to the genotype A.Br.117-4. The strains that caused the cases of the disease in Paninsky District have a common origin with strains 988/717 and 546/714 isolated in the region in the 1980–1990s, and the strains from Bogucharsky District are phylogenetically close to strain 991/178 isolated in 1991 in Dnepropetrovsk Region of Ukraine. The most detailed, to date, topology of the phylogenetic branch of A.Br.117 is described, including four genotypes for which probable time intervals of divergence are determined and the features of the phylogeographic distribution of 165 B. anthracis strains are provided. Strains belonging to the genotype A.Br.117-1 were isolated in Moldova and Ukraine, strains of the genotype A.Br.117-2 predominate in the Central and Southern Federal Districts; strains of genotype A.Br.117-3 – in the Volga, Southern and North Caucasian Federal Districts, and strains of genotype A.Br.117-4 – in the North Caucasian and Southern Federal Districts.

The aim of the work was to improve epidemiological surveillance of tick-borne infections through riskoriented differentiation of territories at the municipal level using new information technologies and GIS technologies. Materials and methods. The work used the data of form No. 2 of the federal statistical surveillance for the period of 2000–2023 in the context of municipalities, obtained from 14 constituent entities of the Russian Federation endemic for three main tick-borne infections (tick-borne viral encephalitis, Ixodidae tick-borne borreliosis, Siberian tick-borne typhus). To calculate risk levels based on average long-term morbidity rates, the computer program “Risk territory: calculation and display of risk territories (as regards infectious morbidity) on the map” developed and patented by the authors and the methodology approved by GOST R ISO 16269-7-2004 were used. Results and discussion. Differentiation of 412 municipalities in 14 constituent entities of the Russian Federation by the levels of risk for the population to contract three tick-borne infections has been carried out. Average long-term indicators of morbidity rates as regards tick-borne infections were calculated, based on the analysis of which threshold values for five risk levels were determined. Classified choropleth cartograms were constructed using the QGIS v.2.18.12 software. Municipalities with different levels of risk for tick-borne viral encephalitis, Ixodidae tick-borne borreliosis and Siberian tick-borne typhus have been identified in the studied constituent entities of the Russian Federation. The results of the study on differentiation of natural-focal areas by the levels of risk of tick-borne infections at the municipal level will allow specialists from the Rospotrebnadzor and healthcare service to more accurately determine the strategy and tactics of anti-epidemic measures.

The aim of the work was to study the presence of anti-phage systems in the genome of non-toxigenic Vibrio cholerae O1 biovar El Tor strains and to determine the resistance of strains with different structures of these systems to the cholera diagnostic bacteriophage El Tor. Materials and methods. The work used 126 non-toxigenic (ctxA– tcpA+ and ctxA^– tcpA^– ) strains of V. cholerae O1 El Tor, isolated from the external environment and from patients with acute intestinal infections in the territory of the Russian Federation and neighboring countries between 1972 and 2018. Sequencing was performed on the MGI DNBSEQ-G50 platform. The following programs were used for bioinformatics analysis: fastp v0.23, unicycler v0.4.7, Blast 2.16.0 and MEGA X. The interaction of the cholera diagnostic bacteriophage El Tor with the surface of bacteria was studied using atomic force microscopy. Results and discussion. Phageinduced PLE islands and BREX systems were not detected in the genome of the studied strains. At the same time, 75 % of ctxA^– tcpA⁺ strains contain type I restriction-modification genes, while those genes were not detected in ctxA^– tcpA^– strains. The CBASS-system genes are present in single strains of both groups. The presence of type I CRISPR-Cas system was established in the genome of 36 (33 %) ctxA^– tcpA^– strains isolated in different regions of our country. Moreover, 78 % of strains containing this system are resistant to the cholera diagnostic bacteriophage El Tor. Thus, heterogeneity of the studied non-toxigenic strains of V. cholerae O1 El Tor in regard to the presence of anti-phage systems has been established, which expands the knowledge on their genetic organization. Non-toxigenic ctxAB^– tcpA^– strains of V. cholerae O1 El Tor are more resistant to the lytic action of the diagnostic cholera bacteriophage El Tor than ctxAB^– tcpA⁺ strains. One of the reasons for such resistance may be the presence of the type I CRISPR-Cas system.

The aim of the study was to differentiate the territory of the Rostov Region according to the potential risk of infection of the population with pathogens of Ixodidae tick-borne borreliosis (ITBB). Materials and methods. The analysis of the epidemiological situation in 2012–2022 was carried out based on the materials provided by the Federal State Budgetary Health Institution “Center of Hygiene and Epidemiology in the Rostov Region” and the Rospotrebnadzor Administration in the Rostov Region. The basis of epizootiological studies was the data from the ITBB monitoring conducted by the employees of the zoological-parasitological team from the Department of Epidemiology of the “Rostov-on-Don Anti-Plague Institute of the Rospotrebnadzor” in 2015–2022 and provided by the “Center of Hygiene and Epidemiology in the Rostov Region” and the “North-Caucasian Plague Control Station of the Rospotrebnadzor”. Conventional epidemiological, zoological and parasitological, gene diagnostics and analytical research methods were used for the work. Results and discussion. The territorial zoning of the Rostov Region has been carried out on the basis of the score-assessment system of the following factors: the magnitude of the epizootic potential, population density, and morbidity within the boundaries of administrative districts. The Rostov Region is a territory with the persistent natural ITBB focus, which has epizootic and epidemic manifestations. In order to improve epidemiological surveillance on ITBB, the territorial zoning of the region based on the risk-oriented approach has been conducted.

The paper discusses the organization of research and educational activities of the Institute “Microbe” during the Great Patriotic War. The main scientific achievements and contribution of the institute’s employees to ensuring the epidemiological well-being of the country are outlined. The methodological basis for the study was the documents from the funds of the “Microbe” Institute and the State Archives of the Saratov Region (SASR). The presented photographic material is published for the first time.

The article is dedicated to the famous scientist-plague specialist Robert Robinson Brubaker. The contribution of R. Brubaker to the study of the plague microbe, his main scientific achievements, as well as his merits as a researcher, teacher, mentor are noted.