The aim of the work wasto analyze key aspects of the implementation of a set of measures to assess the risks of complicating the situation and prevent the importation and spread of cholera in the Republic of Tajikistan.
Materials and methods. The epidemiological analysis of cholera and acute intestinal infections (AII) incidence in the Republic of Tajikistan was conducted based on the reporting materials of the Ministry of Health and Social Protection of the Population of the Republic of Tajikistan and literature data. As part of the monitoring, 214 samples from environmental objects and 32 samples of clinical material from individuals diagnosed with AII were examined using molecular-genetic and bacteriological methods.
Results and discussion. In accordance with the “Comprehensive plan of joint sanitary and anti-epidemic (prophylactic) measures to prevent the importation and spread of cholera in the Republic of Tajikistan”, reconnaissance activities, joint monitoring studies and training of specialists were carried out. During the reconnaissance assessment, patterns of AII morbidity in the Republic of Tajikistan with a high proportion of AII of unknown etiology, features of the water use system were established, “risk areas” for the development of cholera epidemiological complications were identified (districts of the Khatlon region bordering Afghanistan), where monitoring studies for cholera were subsequently conducted. Based on the monitoring results, active circulation of cholera vibrios in water bodies was established: Vibrio cholerae nonO1/nonO139 DNA was detected in 64.5 % of samples, 6 cultures of V. cholerae O1 and 67 – nonO1/nonO139 serogroups were isolated. The etiology of AII was established in 73.9 % of cases with viruses dominating the structure of infectious agents. DNA of NAG vibrios was detected not only in water samples, but also in a sample of clinical material and wastewater from an infectious hospital, indicating human involvement in the circulation of cholera vibrio. Internal risks of the drinking route of transmission and the fecal-oral mechanism of infection spread in the event of cholera introduction into the territory of the Republic of Tajikistan have been established, which determines the need to develop and implement a set of anti-cholera measures.

This literature review provides an aggregate data on pan-genome studies since the early 2000s. In molecular biology and genetics, pan-genome is the totality of all genetic information on a group of organisms (species or monophyletic group of organisms) under consideration. Pan-genome is structurally divided into the “core genome”, which contains the genes present in all studied genetic sequences, the “accessory genome”, which is genes common to most genomes (10–95 %), and the “cloud genome”, genes that are not present in all representatives of the species, or genes that are present in only one of the genomes or found in less than 10 % of genomes. Some authors also call the cloud genome the “accessory genome”, which contains “unnecessary” genes or strain-specific genes. Also, one of the important indicators of genetic diversity within a taxon is the concept of open and closed pangenomes, which allows us to judge intraspecific diversity, which is associated with various genetic events. Thus, pangenomics is a rapidly developing area at the intersection of microbiology, bioinformatics, epidemiology, which opens up new horizons in research. Due to the improvement of sequencing methods, the concept of one “standard” or “reference” genome may be inconsistent and quite limited, therefore, for a complete understanding of the picture and replenishment of data, it is possible to use the concept of pangenomes.

147 human tularemia cases were registered on the territory of the Russian Federation (the relative incidence rate per 100,000 population is 0.1) in 20 regions of the country in 2024. An unfavorable epidemic situation persists in the territories of the Republic of Karelia (50 tularemia cases); an increase in the incidence was recorded in the KhantyMansi Autonomous District – Yugra (58) and in the Sverdlovsk Region (12), which accounts for 81.6 % of all cases of tularemia in the country. 31 cultures of Francisella tularensis were identified in six regions of the Russian Federation. In 2024, 937,962 people were vaccinated and revaccinated against tularemia. In 2025, the high risk of epidemic complications of tularemia will remain in the Central Federal District (Ryazan, Orel and Bryansk Regions), the Southern Federal District (Volgograd, Rostov Regions and the Republic of Crimea), the North Caucasusian Federal District (Stavropol Region), the North-Western Federal District (Arkhangelsk Region, Republic of Karelia, Nenets Autonomous District), Ural Federal District (Sverdlovsk Region and Khanty-Mansiysk Autonomy, District Yugra), Siberian Federal District (Novosibirsk and Tomsk Regions, The Republic of Altai and Altai Territory), as well as in the Donetsk and Lugansk People’s Republics, Zaporozhe and Kherson Regions.

This paper presents a review of modern domestic and foreign studies on the interaction of the plague pathogen with warm-blooded animals and humans. The molecular basis of the ability of Yersinia pestis to evade and suppress factors of innate and adaptive immunity is considered. Information on the main pathogenicity factors acting at different stages of the disease is provided. The role of lipopolysaccharide (LPS) and the pH6 antigen in evading the host’s immune system at an early stage of infection development is noted, as well as the ability of the plague pathogen to overcome the bactericidal action of serum and reproduce under conditions of iron deficiency. The molecular mechanisms of the pathogen’s counteraction to phagocytosis, the ability to reproduce inside macrophages and express virulence factors, as well as the participation of Ail, Pla adhesins and fraction 1 and pH6 antigens in this process are discussed. The role of the type 3 secretion system as the leading virulence factor of Y. pestis is emphasized. The pleiotropic functions of the effector proteins of the type 3 secretion system are shown. They contribute to the slowing down of phagocytosis or disabling its mechanism, inhibition of signaling pathways of the innate immune system, suppression of inflammatory reactions of the host organism. The ability of Y. pestis to suppress the adaptive immune response through the effect on dendritic cells and T-lymphocytes is discussed. The leading role of LPS in the development of toxic shock in case of plague is noted.

The use of laboratory animals plays an important role in diagnostic, experimental and production work. Special attention is currently being paid to compliance with the rules of biological safety, which is a crucial aspect when working with laboratory animals infected with pathogenic biological agents (PBAs) of groups I–II. Every researcher needs to have practical skills when infecting laboratory animals, as well as knowledge of the specifics of each method of infection. The main document regulating the right of legal entities to operate with the agents of particularly dangerous infections in the Russian Federation is SanPiN 3.3686-21 “Sanitary and epidemiological requirements for prevention of infectious diseases”, as well as regulatory and methodological documents and instructions related to safety issues when working with PBA. Sanitary requirements define organizational, sanitary and anti-epidemic (preventive), engineering and technical measures that ensure personal and collective safety and environmental protection. The analysis of the current legislative, regulatory and methodological framework governing the specifics of working with experimental animals infected with PBA will make it possible to take into account all the risks of biological hazard to humans and the environment in a timely manner. An important role is played by the competence of the staff, which is necessary to reduce the biological risks of infecting laboratory animals.

The relevance of the presented work is due to the need to improve epidemiological surveillance of natural focal infections, which pose a serious threat to human health and well-being both in the Russian Federation and around the world. Urbanization and development of the territory of natural foci for economic purposes, disruption of ecosystems as a whole leads to the loss of habitat for numerous species of wild animals and forces them to come into contact with humans and domestic animals, thereby contributing to the spread of diseases among them, as well as the subsequent transformation of natural foci into anthropogenic ones. In this regard, it is important to introduce the latest scientific methods and achievements into the practice of the sanitary and epidemiological service of our country. This study examines modern methods and technological solutions that have great potential for expanding the capabilities of epidemiological surveillance (epidemiological and epizootiological monitoring), as well as creating systems to respond to emerging threats of a sanitary and epidemiological nature, including geographic information systems used for data visualization, analysis of spatial and temporal relationships and forecasting risk areas; remote sensing of the Earth, which allows collecting data on the state of the environment using satellites and unmanned aerial vehicles, which is important for analyzing the circulation of infections; genomic epidemiological surveillance, which allows identifying genetic variants of infectious agents, studying their evolution and determining their epidemiological significance; big data analytics – provides information processing for timely detection of outbreaks of infections; artificial intelligence and machine learning – automate data analysis and improve forecast accuracy; the Internet of Things provides real–time data for continuous monitoring of environmental parameters and human health.

The review of the current microbiological, epidemiological and diagnostic aspects of some endemic mycoses (histoplasmosis, blastomycosis, emergomycosis) found on the African continent is brought forward. Other endemic mycoses (coccidioidomycosis, paracoccidioidomycosis, talaromycosis) have not been described in Africa and can only be imported. Histoplasmosis caused by Histoplasma capsulatum var. capsulatum is widespread in the world, but Africa is the only continent where two variants coexist – H. capsulatum and H. duboisii. The latter is the causative agent of the disease called “african histoplasmosis”. Disseminated forms of histoplasmosis are diagnosed in 5–20 % of HIV-infected individuals. African cases of blastomycosis are caused predominantly by Blastomyces percursus and B. emzantsi species, which differ significantly from the etiologic agents of this disease in North America (B. dermatitidis and B. gilchristii). The number of diagnosed cases of endemic mycoses in Africa has increased significantly in the last decade, which may be due to a new disease, emergomycosis. One of the etiologic agents of this mycosis is the dimorphic fungus Emergomyces africanus. Laboratory diagnostics of endemic mycoses in most African countries is limited due to the lack of experienced personnel and advanced test systems.

The aim is the forecast of the leptospirosis epidemic manifestations for 2025 in the Russian Federation based on an analysis of the long-term incidence and the epizootiological monitoring data from 2024. Leptospirosis foci are a worldwide public health problem. In the Russian Federation, the average annual incidence of leptospirosis for 2000–2024 (excluding 2020–2021) is 0.39±0.084 per 100 thousand population, mainly sporadic cases are registered, mortality remains high and varies from 2.1 to 8.4 %. In 2024, human leptospirosis was established in all federal districts with maximum incidence levels in the North-Western and Southern federal Districts. Infection with pathogenic Leptospira in small mammals and water was detected in 60 subjects of the Russian Federation in all federal districts. The main volume of the population specific prevention falls on the Southern Federal District and accounts 85.5 % from 15,156 vaccinated. Human disease risks persist in areas with active leptospirosis natural foci, especially in the Central, Far Eastern and North-Western Federal Districts. Imported cases of infection are possible both from highly endemic countries and between the territories of the Russian Federation.

The aim of the study was to evaluate approaches and possibilities for differentiating strains of plague agent of the main and non–main subspecies using the method of mass spectrometric analysis.
Materials and methods. 102 strains of Yersinia pestis of 4 subspecies were used in the current work, which were grown on LB agar pH (7.2±0.1) at a temperature of (28±1) °C for (48±1) hours. The mass spectra of the samples were taken automatically with a laser frequency of 60 Hz on a Microflex LT mass spectrometer (Bruker Daltonics, Germany). The spectra were analyzed in the mass range of 2–20 kDa.
Results and discussion. Various approaches to the differentiation of plague microbe strains by subspecies (biovars) using the MALDI-TOF mass spectrometry method have been considered. When using visual analysis for the sample under study, it is not possible to select fragments of the proteinogram that could be considered specific signals for each subspecies or biovar of Y. pestis. Using the cluster analysis of the MALDI Biotyper program, the formation of two separate clusters was noted, including the mass spectra of strains of the main and Caucasian subspecies of the plague microbe. The mass spectra of Y. pestis strains of the central asiatica and ulegeica subspecies are not grouped into separate clusters. When evaluating the informative value of peaks in the mass spectra, it was demonstrated that the same peak has a different weight value for different subspecies (biovars). Thus, the possibility of using different approaches in the analysis of protein profiles of Y. pestis strains for their differentiation by subspecies and/or biovars has been examined.

Currently, cholera remains a relevant infectious disease that requires special vigilance from healthcare professionals and sanitary-epidemiological services. In this regard, the ability to track the likely spread of strains when imported, identify the link between epidemic outbreaks or isolated cases of the disease, and assess the origin of the isolated strains is of particular interest. Phage typing is one of the tools for solving such problems.
The aim was to conduct phage typing of strains of cholera vibrios of serogroup O1 received by the Reference Center for Cholera Monitoring in 2024.
Materials and methods. The work used 300 non-toxigenic strains of Vibrio cholerae O1 El Tor, isolated from environmental objects in various regions of the Russian Federation during monitoring studies for cholera in 2024. Sensitivity to diagnostic bacteriophages classical, El Tor, typing and experimental phage cocktails was determined.
Results and discussion. The studies have shown that 100 % of the strains were resistant to the classic diagnostic cholera bacteriophage, while 17 % were sensitive to the El Tor phage. The use of typing cholera bacteriophages made it possible to determine the phage types of 11 cultures (in Rostov-on-Don – the eleventh one, in Elista, Republic of Kalmykia – the fourth and first ones, in the Donetsk People’s Republic – the twelfth, in the Kherson Region – the seventeenth), which amounted to 5.6 % of the total. At the same time, phage types were identified that had not previously been encountered in the territories of these entities of the Russian Federation, which indicates the imported nature of the isolated strains. 42 cultures were sensitive to the components of the experimental phage cocktails K1 and K2 (K1 – 8 %, K2 – 6 % of all strains). The results of the conducted studies indicate an increase in the phage resistance of the isolated strains of cholera vibrios and the relevance of a regular search for new bacteriophages with an assessment of the possibility of their use as components of diagnostic and prophylactic drugs.

The aim of the study was to determine the natural boundary of the focal territory, in particular, the boundary between the Precaspian sandy and Dagestan plain-piedmont natural foci of plague. There are 11 natural plague foci that are fully or partially located on the territory of the Russian Federation, most of which share common borders. However, in many cases, it is not possible to establish a natural boundary of the focus, so a formalized boundary is drawn outside the presumed passage. Such uncertainty can lead to difficulties in organizing the examination of foci, implementing preventive measures, and to misinterpretation of survey results and inappropriate use of predictive models. Objectives: to construct ecological niches of the parasitic systems of both foci and to define the boundary between them.
Materials and methods. Archival data from the Stavropol Anti-Plague Institute, Dagestan, Elista, and Astrakhan Plague Control Stations of the Rospotrebnadzor regarding the epizootic manifestations of plague in the foci over the past 35 years were used. Information on abiotic and biotic factors was obtained from open databases on the Internet. Ecological niche models of the foci were constructed using artificial intelligence elements.
Results and discussion. The studied area is proposed to be classified as part of the Dagestan plain-piedmont natural focus of plague, and new outlines of the boundary between the foci are put forward.

The aim of the work was to clarify the species spectrum and assess the epizootiological and epidemiological significance of Ixodidae ticks in the Saratov Region.
Materials and methods. Ticks collected from natural biotopes and obtained from population in 2014–2024 were examined by molecular-genetic and serological methods for the presence of pathogens of natural focal diseases. Then, the infection rate was calculated, and the epidemiological significance of various Ixodidae tick species was determined.
Results and discussion. DNA markers of pathogenic Borrelia, Coxiella, Rickettsia of the tick-borne spotted fever group, and the tularemia pathogen antigen have been identified. The importance of various tick species as vectors of pathogens of borreliosis and tularemia is shown. In the Saratov Region, Ixodes ricinus and Dermacentor reticulatus play a key role in the transmission of Borrelia, while D. reticulatus and Rhipicephalus rossicus are vectors of tularemia. Promising areas of research related to Ixodidae ticks include identifying the spread of Rickettsia in the region and studying their ecological features, identifying Francisella-like endosymbionts of Ixodidae ticks, and studying the biological and ecological features of individual species of the family Ixodidae. Determining the role of these ticks in the circulation and spread of tick-borne spotted fever Rickettsia is relevant in regional pathology

In the Russian Federation, human cases of the tick-borne spotted fever group (SFG) rickettsioses are reported annually, and endemic foci of SFG rickettsioses exist, including Siberian tick typhus, Astrakhan spotted fever and Mediterranean (Marseilles) fever, which highlights the epidemiological significance of these infections. The Saratov Region is an endemic one for several natural-focal diseases (Ixodidae tick-borne borreliosis, West Nile fever, etc.) and demonstrates climatic and landscape-geographical conditions favorable for the spread of tick-borne pathogens. However, until now, no data were available on the circulation of SFG rickettsiosis in this region.
The aim of the work was to detect genetic markers of pathogens of tick-borne spotted fever group rickettsioses in tick samples collected during epizootiological monitoring of natural focal infections in the Saratov Region between 2021 and 2024.
Materials and methods. For this study, 4582 specimens of Ixodidae ticks and gamaside mites belonging to 14 species were collected from 10 districts of the Saratov Region and municipal settlement “Saratov city”, pooled into 1055 samples. PCR was used to detect genetic markers of Rickettsia spp. SFG and Rickettsia conorii.
Results and discussion. Genetic markers of SFG rickettsioses have been detected for the first time in the Saratov Region. DNA of Rickettsia spp. SFG were identified in 262 (26 %) samples from 11 tick species, collected across all surveyed areas. DNA markers of R. conorii were found in 23 (2.3 %) pooled samples from two tick species, obtained from three districts of the region and the Saratov municipality. These findings suggest the potential circulation of SFG rickettsioses in the Saratov Region and emphasize the need for further studies of the distribution, diversity and vector associations of pathogenic Rickettsia species in the region.

In 2024, during routine monitoring of surface water bodies in Sochi for cholera, non-toxigenic cholera vibrios of serogroup O1 were isolated.
The aim of the work was to analyze the results of the epidemiological monitoring and characterize the molecular-genetic properties of the isolated strains.
Materials and methods. The work uses the data obtained as a result of an epidemiological investigation of the causes of river contamination with cholera vibrios in Sochi. Whole-genome sequencing of isolated strains was performed on the MiSeq platform (Illumina). Genetic determinants of cholera vibrio pathogenicity were identified using the BioEdit and BLASTN software.
Results and discussion. It was established that the probable cause of contamination of the Matsesta river waters was the entry of non-toxigenic cholera vibrios from patients with a mild course of the disease, with an erased form of the disease or vibriocarriers. The introduction of cholera vibrios into the Agura and Mzymta rivers could have occurred due to associated groundwater, since a karst aquifer lies in the waters of all three rivers. Bioinformatics analysis showed that the isolated cultures of cholera vibrios in the waters of the Matsesta, Agura and Mzymta rivers are genetically identical, constitute a single clonal complex with strains isolated from surface water bodies of the Russian Federation, and are not imported from abroad. Vibrio cholerae O1 strains isolated from environmental objects in 2024 and cultures isolated from patients with acute intestinal infection (AII) in the Kherson Region (2024) and Krasnodar Territory (2004) belonged to the same cluster. The results indicate the presence of optimal environmental conditions for the existence of cholera vibrios in the surface water bodies of Sochi, which necessitates extensive monitoring to its maximum, provided for type I territories for epidemic manifestations of cholera, with prompt molecular-genetic study of the isolated cultures.

The aim of the work was to analyze the development of the epidemiological situation on a new coronavirus infection in the Republic of Buryatia during the COVID-19 pandemic from 2020 to 2023.
Materials and methods. We used the data from weekly monitoring of laboratory-confirmed cases of COVID-19 (patients and carriers), as well as the results of molecular-genetic typing of the pathogen that circulated in the constituent entity in the period of 2021–2023. Statistical and analytical calculations of epidemiological indicators were carried out using Microsoft Excel and RStudio software.
Results and discussion. Seven waves of the COVID-19 pandemic in the Republic of Buryatia have been characterized; key periods of the II and V waves of COVID-19 incidence, when the number of people involved in the epidemic process reached peak values, have been identified. There was a tendency towards a steady decrease in the incidence of community-acquired pneumonia with confirmed COVID-19, the frequency of hospitalization and the mortality rate starting from the III wave of incidence. The time lag for changes in the epidemic situation in the Republic of Buryatia relative to the Russian Federation was about one week, which was explained by the ongoing active labor migration of the population within the Russian Federation. Most often, females were involved in the epidemic process; among age groups – children under 1 year old and adolescents 15–17 years old, as well as people 50 years and older. During the pandemic, the mild form of COVID-19 prevailed; the proportion of severe cases of the disease throughout the pandemic did not exceed 1.0 %. The main risk groups were pensioners, workers and individuals falling under the “others” category. The predominant sourse of suspected infection was family and close circle.

The aim of the work was to develop an indirect method for identifying viable cholera vibrios by evaluating the titer increase of a specific bacteriophage detected in RT-PCR.
Materials and methods. The cholera bacteriophage Rostov M3 was used for the study (myovirus class Caudoviricetes; GenBank: MN379460.1-MN379463.1). The study of biological properties was carried out using conventional methods with minor modifications. Primers for phage amplification were designed using https://bioinfo.ut.ee/primer3-0.4.0. Cultivation of samples containing viable and non-viable Vibrio cholerae with bacteriophage was carried out in 1 % peptone water for times Т₀ and Т_n. The PCR result was expressed as the number of phage particles per ml of sample or as the Cp value.
Results and discussion. Bacteriophage Rostov M3 has a high adsorption rate and yield, and also has a broad spectrum of lytic activity against V. cholerae O1 Classical and El Tor. During the accumulation of Rostov M3 phage particles, a decrease in the Cp value was recorded when the sample was incubated for at least two hours. In this case, a conclusion is made about the presence of viable V. cholerae in the sample. Using this method, it is possible to identify bacterial cells that are in a living but non-culturable state, since phages retain the ability to reproduce in this cell phenotype. The application of the proposed method to inactivated cultures (negative control) of V. cholerae did not show an increase in the number of phage particles relative to the zero point, therefore a conclusion is made about the absence of viable cells in the sample. The authors put forward the method that allows one to establish the difference in the levels of accumulation of phage particles when studying samples containing live and non-live V. cholera O1 bacteria in contact with the Rostov M3 bacteriophage for a certain period of time Т₀ and Т_n. The developed method allows for expanding the possibilities of indirect detection of viable V. cholerae O1 Classical and El Tor in potentially contaminated objects.

The aim of the work was to assess the epidemic situation on hemorrhagic fever with renal syndrome (HFRS) in the Republic of Tatarstan and to divide the republic’s territory into zones according to the degree of potential risk of infection of the population.
Materials and methods. The analysis used archival data on HFRS incidence in the Republic of Tatarstan since the onset of HFRS registration in 1959 until 2024, state statistical reporting form No. 2 “Information on infectious and parasitic diseases” for each year of the period 2015–2024, and the results of epizootiological (for 2014–2024) and serological (for 2012–2024) monitoring.
Results and discussion. The work presents the results of the epidemiological analysis of the epidemic situation on HFRS in the Republic of Tatarstan for the purpose of epidemiological zoning of municipal districts according to the degree of potential risk of HFRS infection. The obtained results of the analysis allow for compiling a cartogram of the republic, identifying regions with different levels of epidemic risk of infection of the population. The obtained materials can be used to predict the epidemic situation and to carry out early preventive measures aimed at reducing the incidence among the population.

The aim of the study was to conduct comparative phylogenetic analysis of Francisella tularensis subsp. mediasiatica strains isolated in different territories of contemporary Republics of Kazakhstan, Uzbekistan, Altai Territory, and the Altai Republic in the period between 1960 and 2024.
Materials and methods. We used 77 F. tularensis strains isolated in the territories of Kazakhstan, Uzbekistan, Altai Territory and the Altai Republic of the Russian Federation in the period from 1960 to 2024. To determine the subspecies, the INDEL typing method was used. VNTR genotyping was carried out at 5 loci. Identification of clonal complexes was carried out using the MST method.
Results and discussion. Comparative analysis of VNTR genotypes of 42 F. tularensis subsp. mediasiatica strains circulating in natural foci of Altai between 2011 and 2024 made it possible to identify three clonal complexes (CC1-CC3), represented by 13, 14 and 7 individual genotypes, respectively. Strains of the “Kazakhstan” population of F. tularensis subsp. mediasiatica are represented by a separate clonal complex CC4. It has been established for the first time that the “Altai” population of F. tularensis strains of the subspecies mediasiatica is represented by three clonal complexes CC1-CC3. In the same territories of the Altai region, strains of different clonal complexes can circulate at different times. High genetic diversity of the Altai population subsp. mediasiatica was noted (Nei diversity index DI = 0.991). For the first time, a comparable phylogenetic analysis of the “Kazakhstan” and “Altai” populations of the causative agent of tularemia subsp. mediasiatica has been carried out. It is shown that the “Kazakhstan” population forms a separate clonal complex CC4 and it is connected with the Altai clonal complexes through different clones. The results of genotyping indicate the possible origin of the “Altai” population of mediasiatica subspecies.

The aim of the study was to determine the species affiliation and genetic diversity of pathogens of bacterial natural focal infections in order to refine the spectrum of circulating agents in certain areas of the Kherson and Zaporozhe Regions.
Materials and methods. An epizootiological survey of the territory of Verkhnerogachik, Genichesk, Novotroitsk districts of the Kherson Region, Akimov, Berdyansk, Vasilievsk, Veselovsky, Melitopol, Pologovsky districts of the Zaporozhe Region was conducted. The study of field material was carried out by molecular-genetic, serological, and biological methods. Sequencing of Borrelia DNA isolates by a fragment of the 16S rRNA gene, fragments of genes (gltA, ompB) of Rickettsia spp. DNA isolates, MLVA-25 typing of Francisella tularensis strains were performed. Statistical analysis of the laboratory test results was performed using Microsoft Excel 2010. The data were analyzed using the cartographic method applying ArcGIS 10.3.
Results and discussion. The circulation of pathogens of tularemia, leptospirosis (Leptospira icterohaemorrhagiae, L. grippotyphosa), rickettsiosis (Rickettsia aeschlimannii, R. heilongjiangensis, R. conorii, R. slovaca, R. vini), Ixodidae tick-borne borreliosis (Borrelia afzelii, B. miyamotoii) in individual areas of the Kherson and Zaporozhe Regions has been established. Markers of Anaplasma phagocytophilum have been identified in the Zaporozhe Region. The data obtained indicate a possible joint circulation of pathogens of leptospirosis, tick-borne rickettsiosis, Ixodidae tick-borne borreliosis in the Genichesky district of the Kherson Region; tularemia, leptospirosis, tick-borne rickettsiosis, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis in the Melitopol district of the Zaporozhe Region; leptospirosis, tick-borne rickettsiosis, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis in the Berdyansk district of the Zaporozhe Region. Based on the results of the conducted studies, information on the circulation of pathogens of tularemia, leptospirosis, rickettsiosis, Ixodidae tick-borne borreliosis in certain areas of the Kherson and Zaporozhe Regions has been obtained, which suggests the presence of foci of combined infections. Outbreak and sporadic incidence of natural focal infections is possible in the surveyed area. To assess the epidemic potential of territories, further epizootiological examination, assessment of the number and species composition of carriers and vectors of pathogens of natural focal infections, and an analysis of morbidity are required.

Ixodidae tick-borne borreliosis (ITBB) is the most common transmissible disease in the Northern Hemisphere. The study of the features of the biocenotic structure and functioning of natural foci of ITBB in the steppe and dry steppe zones is of particular interest. The territory of the Azov Lowland is a plain with a steppe type of landscape. In 2023–2024, on most of that area, employees of the Rostov-on-Don Anti-Plague Institute of the Rospotrebnadzor conducted epizootiological monitoring of natural focal infectious diseases, including ITBB.
The aim of the work was to study the state and structure of the natural focus of ITBB in the steppe zone of the Azov Lowland.
Materials and methods. The work used the results of the epizootiological survey. The study was carried out using epidemiological, zoological, genetic diagnostic and statistical methods.
Results and discussion. It has been established that the main carriers of borreliosis pathogens in the ITBB natural focus of the Azov Lowland are small mammals: house mouse, European wood mouse, small wood mouse, yellow-necked mouse, lesser white-toothed shrew and gray hamster. The main carriers are Ixodidae ticks, Ixodes redikorzevi and Ixodes ricinus. This ITBB focus is of anthropourgic nature and stays in an active state. It is characterized by a low level of potential danger of infection of people with borreliosis pathogens.

The aim of the study was to assess the epidemiological situation and to characterize the potential epidemic hazard in the foci of Siberian tick-borne typhus (STT) in the Minusinsk Basin (Krasnoyarsk Territory and the Republic of Khakassia).
Materials and methods. The analysis of the STT incidence rates per 100 thousand population in administrative districts of the Minusinsk Basin between 2013 and 2022 was carried out. Ticks (n=182) collected on a flag in the territory of the Minusinsk basin and sectional material from the patient were studied using the PCR method with a set of genus- and species-specific primers to identify various types of Rickettsia followed by sequencing of the obtained amplicons.
Results and discussion. The average long-term incidence rate of STT in the Minusinsk Basin is 11.8 ⁰/₀₀₀₀ (95 % CI 11.4–12.2). The maximum incidence of STT occurs in May and June, which is determined by early seasonal activity of the main vector, the Dermacentor nuttalli tick. The PCR analysis has revealed a total DNA detection of Rickettsia at 79.2 %. Rickettsia sibirica, R. helvetica and R. raoultii DNA has been detected in D. nuttalli. Haemaphysalis concinna contains DNA from R. heilongjiangensis, R. sibirica and R. raoultii. In the study of the Ixodes persulcatus ticks, Candidatus R. tarasevichiae has been identified in all positive samples. D. silvarum specimens contained DNA from R. sibirica, R. raoultii, and Ca. R. tarasevichiae. DNA from R. sibirica subsp. sibirica was identified in sectional material from a STT case with fatal outcome. The activation of the epidemic process in in the Minusinsk Basin (Krasnoyarsk Territory and the Republic of Khakassia) is due to epidemiological risks (high activity of D. nuttalli ticks and the total rickettsiophority of R. sibirica vectors, documented fatal cases, circulation of highly virulent strains of R. sibirica) with their transition from potential to actual.

The aim of the work was to identify and analyze failures of microbiological safety cabinets and supply and exhaust ventilation systems in bacteriological laboratories.
Materials and methods. The technical condition and integrity of the HEPA filters of the microbiological safety cabinets and air purification filters for supply and exhaust ventilation were checked in accordance with the requirements of articles 188–191 of SanPiN 3.3686-21, GOST R EN 12469-2010. Over the period of 2018–2023, 926 studies were conducted to verify the protective effectiveness of microbiological safety cabinets and air purification filters; of those, microbiological safety cabinets class 1, 2, 3 – 524 units, filters for air purification of supply and exhaust ventilation – 402. The inspection was performed using the following bits of equipment (measuring instruments): Solair 3100 portable particle counter, Atomizer Aero Generator ATM 226 test aerosol generator, Dilution System DIL 554 aerosol diluent, Testo 510 differential pressure gauge.
Results and discussion. As a result of the study conducted, it was established that out of 524 cabinets, 488 units (93 %) met the requirements of sanitary regulations and were approved for further use. 36 microbiological safety cabinets did not pass the test for compliance with the requirements of sanitary rules and regulations by the following parameters: the incoming flow rate – 4 units, the downward flow rate – 6 units, and the protective efficiency of the filter – 26 units. Of the 26 cases of the protective effectiveness violation of the air purification filters in the microbiological safety cabinets, 15 filters had their integrity compromised at one or 2–3 surface points, and 6 pieces of equipment had diffusely damaged entire filter surface. 5 pieces of equipment had a leak of test aerosol around the perimeter of the installation and breach of the sealing of the filter in the housing of the cabinet.

The Battle of Stalingrad was the greatest battle of the Great Patriotic War, which halted the offensive movement of German troops across our land. The victory at Stalingrad was a heroic achievement not only of the Soviet armies and fronts, outstanding commanders-in-chief, commanders and ordinary soldiers who fought for the Motherland, but also of military and civilian doctors who did not spare themselves to save the lives of wounded soldiers. A huge contribution to the protection of soldiers and townspeople of Stalingrad was made by workers of the sanitary and epidemiological service. In a totally destroyed city, which lacked basic sanitary conditions, they tirelessly fought against infectious diseases that posed a threat to the army and the civilian population. The article is dedicated to the memory of our colleagues of past years, whose selfless work made it possible to prevent the mass spread of dangerous infectious diseases, including cholera, tularemia, and typhus, during the brutal battles near Stalingrad.