The epidemiological hazard of orthopoxviruses and the side effects of the used live vaccines are growing, raising the safety requirements for vaccination.

The aim of this review was to analyze ways to improve the safety of smallpox vaccines. Biotechnological improvement of dermovaccines did not enhance safety to an acceptable level and caused the introduction of a large number of restrictions, contraindications, and eventually a ban on their use. The improvement of parenteral vaccines is dominated by the biotechnological trends of safety increment, which, combined with the immunological correction of the vaccination method (two-stage vaccination in Russia or multiple immunization abroad), contributed to achieving acceptable safety requirements for the third generation of smallpox vaccines. The failures of biotechnological improvement of dermovaccines led to the intensification of research on the development of third-generation oral vaccines of the TEOVac type, meeting the principles of safety and effectiveness, and further development of the immunological aspect of higher vaccination safety. The implementation of the immunological course for improving the safety of anti-smallpox vaccines was carried out through the development of oral mucosal vaccines and a two-stage vaccination method. Another problem with the specific prevention of smallpox is the high risk of complications after vaccination. A two-stage or two-fold method of vaccination with epidemiologically effective live vaccines is a universal solution for the relief of such complications. In the USA, a supply of homologous immunoglobulin has been created and chemotherapy drugs are being produced to relieve complications; in the Russian Federation, only the NIOX‑14 drug is currently licensed, and attempts are being made to compensate for the absence of homologous immunoglobulin with a heterologous purified drug. Thus, for Russia, the most effective and promising area for improving the safety of smallpox vaccines is immunological one: the development of a modern oral method of immunization, mucosal vaccines and a two-stage vaccination method. Abroad, the biotechnological trends in improvement of parenteral smallpox vaccines dominate, which is complemented by the immunological one.

This review systematizes the data on the development and implementation of mobile technologies for rapid response to sanitary and epidemiological emergencies. It examines practical experience in using mobile laboratories to eliminate biological threats both in the Russian Federation and in neighboring and far abroad countries. To date, mobile biological laboratories are one of the tools used to respond to public health emergencies. They can operate autonomously anywhere in the world, performing thousands of tests per day using advanced laboratory diagnostic methods. Since 2006, Federal Service for Surveillance on Consumers Rights Protection and Human Wellbeing, together with the Russian AntiPlague Institute “Microbe” of the Rospotrebnadzor, has been developing and creating mobile laboratories mounted on truck chassis and pneumatic frame systems. Currently, 21 types of mobile laboratories have been developed and are in use in infectious disease foci, natural disaster zones, during elimination of humanitarian and man-made disasters, and to ensure safety during mass events with international participation. Russia’s experience in deploying mobile laboratories is in demand abroad. Mobile laboratories were used to eliminate the Ebola virus disease in the Republic of Guinea, to decipher an outbreak of intestinal infection in the Republic of the Congo, to ensure sanitary-epidemiological well-being in Lebanon during the emergency response to a complex man-made disaster amid the COVID-19 pandemic, and to combat the novel coronavirus pandemic. Further development and improvement of mobile technologies will expand their capacities in the fight against infectious diseases.

The review presents the current global epidemiological situation, with a focus on the risks of importation of dangerous infectious and parasitic diseases into the Russian Federation. The analysis is based on data from international organizations, national health authorities, scientific publications, and electronic outbreak reporting systems. Probabilities of disease importation were estimated taking into account passenger traffic and the epidemiological status of source countries. The findings are structured according to the six regions, following the World Health Organization regional classification. When describing the relevant region, the general causes of epidemiological problems and the contribution to global morbidity are briefly outlined, the largest outbreaks are described, and gaps in the scientific community’s understanding of the true incidence of a number of infections in various territories are noted. The synthesized conclusions may be of practical value to professionals involved in border sanitary protection and epidemiological surveillance in the context of preventing the spread of infectious threats. The analysis underscores the ongoing need to improve approaches to sanitary protection measures in response to evolving epidemiological threats. These threats are driven by persistent risks of importing well-known infections from endemic countries, the resurgence of previously controlled diseases, the emergence of novel pathogens, and the geographic expansion of infections into previously non-endemic areas.

The review presents an assessment of the epidemiological and epizootiological situation regarding Q fever in the Russian Federation for the period from 2013 to 2024, excluding the data for 2020 and 2021 due to anti-epidemic measures aimed at COVID-19, as well as covers current aspects of combating this infection. An evaluation of the epidemic potential of Q fever in Russia and other countries, where an increase in activity of infection foci has been observed, is made. Ranking of the Q fever-affected regions in the Russian Federation has been carried out based on morbidity rates, with a very high level of epidemic risk noted for Astrakhan Region (average long-term morbidity rate is 9.31 per 100 thousand population). An analysis of Q fever cases in Russia during 2024 has revealed 286 registered cases (0.20 per 100 thousand population), where Stavropol Territory contributed significantly to the total number of Coxiella infections – 138 cases (4.78) – and Astrakhan Region added another 127 cases (13.39), accounting for 92.7 % of all recorded cases. Q fever registration within the territory of the Russian Federation occurred from March through December 2024 inclusively, reaching its peak in June–July. The results of monitoring Q fever in the Stavropol, Altai, and Primorsk Territories as well as Astrakhan, Rostov, and Omsk Regions are provided in the paper. Antibodies of class G against Coxiella burnetii were detected in blood serum samples taken across all surveyed areas. In the Astrakhan Region, markers (DNA) of C. burnetii were found in sheep wool and skin samples, feeding stuff, milk, soil, and bedding used by farm animals. Overall, DNA/antigen of C. burnetii was identified in 5.3 % of Ixodidae tick samples collected across six regions.

The aim of the review was to conduct a comparative analysis of the epidemiological situation regarding rickettsioses in the constituent entities of the Russian Federation for the period of 2013–2024, and to provide a forecast of the incidence for 2025. In total, 1,380 rickettsiosis cases were registered in the Russian Federation in 2024, of which Siberian tick-borne typhus (STT) accounted for 938 cases, Astrakhan spotted fever (ASF) – 73 cases, rickettsiosis caused by Anaplasma phagocytophilum – 12 cases, rickettsiosis caused by Ehrlichia chaffeensis and Ehrlichia muris – 8 cases, Marseille fever – 6 cases. 57 (4.1 %) cases of rickettsiosis remained unidentified. In 2024, STT was recorded in 17 regions of the Russian Federation with an incidence rate of 0,64 ⁰/₀₀₀₀. The greatest contribution to STT morbidity came from the Siberian and Far Eastern Federal Districts. The calculated projected indicator for 2025 in Russia is expected to be 0.67 ⁰/₀₀₀₀. The ASF morbidity rate in Russia in 2024 was 0.05 0 /0000, while the calculated projected ASF morbidity rate for 2025 remains at 0.05 ⁰/₀₀₀₀. In 2024, it was possible to verify the causative agent of STT in autopsy material from three deceased individuals from Tyumen Region (n=1) and Novosibirsk Region (n=2). As a result of phylogenetic analysis, a new genovariant (genome isolate) of Rickettsia sibirica was identified in one sample.

The aim of the study was to investigate the genetic variability of p66 gene loci in Borrelia bavariensis isolates obtained from adults and nymphs of Ixodes persulcatus ticks, as well as from nymphs of I. trianguliceps.

Materials and methods. 123 isolates of B. bavariensis from nymphs and adults of taiga tick and from nymphs of I. trianguliceps collected in 1993–2003 in the natural focus of Ixodid tick-borne borreliosis (ITBB) of Perm Territory were studied. Nucleotide sequences were obtained using polymerase chain reaction followed by sequencing of p66 gene loci amplicons. The results were analyzed applying BLAST service. The dendrogram was constructed using the maximum likelihood method in MEGA11 software (a bootstrap value of 1000 repeats).

Results and discussion. Among the studied isolates, 8 allelic variants of p66 gene loci of B. bavariensis were found, 6 of which were in the adult taiga ticks. Isolates from nymphs of I. trianguliceps have an almost similar set of such variants as isolates from nymphs and adults of I. persulcatus. In isolates from nymphs (70.0±7.2 %) and adults (67.2±6.2 %) of the taiga tick, allelic variants No. 1 and 2 were more frequent. They also prevailed among isolates from I. trianguliceps nymphs (76.0±17.4 %). In the studied natural focus, I. persulcatus and I. trianguliceps ticks maintain the circulation of various allelic variants of Borrelia bavariensis, which is confirmed by the presence of corresponding p66 gene loci in them. Variants No. 1 and 2 are identical to those previously detected in isolates B. bavariensis from humans with ITBB (Golidonova et al., 2022). The significant prevalence of the two identified allelic variants of Borrelia in tick vectors during circulation of the pathogen in the natural focus explains the most frequent infections of population with ITBB by these variants.

The aim of the work was to detect antibodies to the West Nile fever (WNV) agent in horse blood sera collected in selected areas of the southern and central regions of the European part of Russia.

Materials and methods. A competitive enzyme immunoassay was used to test 396 horse blood sera samples from 7 constituent entities of the Russian Federation: the Republics of Adygea, Kalmykia, Mordovia, as well as Kaluga, Oryol, Orenburg and Kirov Regions for the presence of total antibodies to West Nile virus (WNV).

Results and discussion. Contact with the WNV was confirmed in horses in 4 regions of Russia. The average immunity level to WNV was 8.3 % (95 % CI: 4.4–12.3). The highest frequency of antibodies to the WNF pathogen was registered in the Republic of Kalmykia (27.8 %; 95 % CI: 14.6–41.0), including the city of Elista (13.6 %; 95 % CI: 7.2–20.1), Iki-Burulsky and Tselinny districts (48.0 % each; 95 % CI: 25.2–70.8). The proportion of seropositive horses in the Republic of Kalmykia is comparable in its values with the indicators obtained in earlier studies in the Volgograd and Astrakhan Regions. In the Kirov Region, the proportion of positive samples was 2.0 % (95 % CI 1.1–2.9), in the Oryol Region – 2.0 % (95 % CI: 1.1–3.0), and in the Republic of Mordovia – 8.0 % (95 % CI: 4.2–11.8). Until 2024, there was no evidence of local circulation of WNV in these regions. Serological testing of horses is important for obtaining an objective assessment of the intensity and prevalence of the WNV epizootic process in Russia.

The effectiveness of tularemia prevention in humans depends on the timely detection of pathogen cultures in natural foci.

The aim of the study was to increase the efficiency of isolating Francisella tularensis cultures during epizootiological monitoring in natural foci of steppe type through taking into account the dependence of the infection rate of carriers, vectors and environmental objects on the degree of epizootic activity and the survey season.

Materials and methods. An epizootiological survey was conducted in the Stavropol Territory in the period of 2003–2018. A total of 5,692 small mammals, 865 bird pellets and droppings of predatory mammals, 71,387 adult Ixodidae ticks, 94 water samples from local water supplies and 93 field samples from other environmental objects were tested for tularemia.

Results and discussion. F. tularensis cultures were isolated from Ixodidae ticks collected in spring (88.2 %) and summer (12.8 %), from small mammals – mainly in autumn and winter (43.7 % each, respectively), from environmental objects – in winter. All isolates were identified as F. tularensis holarctica, biovar II. During diffuse epizootics in winter in the first quarter of 2017, 23 strains of F. tularensis were isolated. Infection rate among small mammals was 5.7 % of specimens, for water samples from local water supplies – 28.8 %, and for hay and forage samples – 16.6 %. During local epizootics, 31 strains of F. tularensis were isolated. Infection of small mammals was 0.14 %, water samples from local water supplies – 11.9 %, and Ixodidae ticks – 0.024 % of specimens. In the natural steppe tularemia focus, the intensity of epizootics increases in the autumn-winter period, and the most effective way to isolate F. tularensis cultures is to study small mammals and environmental objects. In the spring-summer period, when epizootics do not occur, adult Ixodidae ticks must be studied.

The aim of this study was to determine the comparative aspect of the diversity of flea species, their distribution and abundance based on the results of epizootiological survey conducted in the Absheron and Kobystan meso-foci of plague.

Materials and methods. The study material was flea samples obtained during epizootiological observation and examinations carried out by employees of the epidemiological group of the Centre for Control of Particularly Dangerous Infections in the spring (May-June) and autumn (September-October) seasons of 2020–2024 from the mesofoci of plague located on the territory of the Absheron Peninsula – Kobystan and Absheron ones, with a total area of 6,700 hectares and 11,300 hectares, respectively. The ecological and faunistic characterization of fleas was performed on the basis of a study of a data set reflecting their biological, ecological and taxonomic features. The flea abundance index in the studied areas was calculated. The testing of ectoparasite samples for the presence of Yersinia pestis was carried out using bacteriological and molecular-genetic (PCR) methods. A total of 3,797 samples from 21,421 rodent nests were examined.

Results and discussion. It has been established that the Kobystan and Absheron meso-foci of plague differ slightly from each other in flea fauna. Fleas of the genus Xenopsylla conformis are the dominant species in both studied foci, with variations in numbers by season and territory. Reliable differences were found for most species in terms of seasonal dynamics. Statistically significant most pronounced fluctuations were found for X. conformis (χ²=916.2, p<0.0001) and Mesopsylla apscheronica (χ²=207.4, p><0.0001). Annual and seasonal peaks of the index were identified, indicating periods of increased risk of transmission of plague pathogen. The established reliable differences in flea species confirm the need to take into account local and seasonal factors when planning preventive and sanitary measures in the studied meso-foci. Key words: plague, Absheron meso-focus, Kobystan meso-focus, abundance index, ecological and faunistic features> < 0.0001) and Mesopsylla apscheronica (χ²=207.4, p < 0.0001). Annual and seasonal peaks of the index were identified, indicating periods of increased risk of transmission of plague pathogen. The established reliable differences in flea species confirm the need to take into account local and seasonal factors when planning preventive and sanitary measures in the studied meso-foci.

The aim of the work was to study biological, molecular-genetic properties and to determin the phylogenetic affiliation of Brucella abortus strains isolated in the Volga and Central Federal Districts.

Materials and methods. A research of 21 strains of B. abortus isolated in the Volga Federal District and the Central Federal District in 2017–2024 was conducted. Genome sequencing was performed on the DNBSEQ G50RS platform (MGI, China) using the MGI Easy FAST FS DNA Library Prep Set V2.1 reagent kit (MGI, China) according to a standard protocol. Phylogenetic reconstruction was performed using the maximum likelihood method in the “RealPhy” software.

Results and discussion. All strains have tinctorial, morphological, and cultural properties characteristic of typical B. abortus strains. The topology of the phylogenetic tree indicates the common origin of the strains isolated in the Volga Federal District and the Central Federal District in 2017–2024. It has been found that the studied isolates are genetically close to the B. abortus strains isolated from biomaterial from animals with brucellosis and food products of animal origin from the Lipetsk Region (2017), Samara Region (2016), Stavropol Territory (2015), Republic of Dagestan (2015), Republic of Kalmykia (2012). The general clustering of strains from the Volga Federal District and the Central Federal District and from different entities of the North Caucasus Federal District and the Southern Federal District indicates the presence of a retrospective epidemiological link between brucellosis foci and the affected over the long period territory of the southern European part of Russia, including the North Caucasus.

The Karakum autonomous desert plague focus, located on the territory of Turkmenistan, is characterized by the periodic development of local epizootics with the possible emergence of epidemic complications. Due to climate warming, the structure of rodent communities and the course of their long-term population dynamics have changed. Social problems have also changed, in particular, there has been a significant territorial redistribution of the population, associated with its modern confinement to relatively few permanent sources of fresh water.

The aim of this work is to study the influence of ambient temperature, precipitation and vegetation on the population dynamics of the Yersinia pestis carrier – the great gerbil (Rhombomus opimus) and its fleas in the Eastern Karakum.

Materials and methods. This paper presents long-term zooparasitological research data obtained during annual expeditions conducted in the spring and fall at the Repetek State Biosphere Reserve, located in the Eastern Karakum Desert. A total of 182 expeditions were organized, with capturing of 1,600 great gerbil specimens. A route-colony method was used to determine colony density. At least two survey routes were laid out within the surveyed area.

Results and discussion. Air temperature and vegetation growth in the Eastern Karakum Desert fluctuated in waves – periods of rising temperatures were replaced with periods of decreased average annual values, followed by fluctuations in plant growth seasons. The state of the great gerbil’s food supply directly impacted its population. During a decline in the great gerbil population, the frequency of mating and other intrapopulation contacts decreased. Monitoring of fleas living in the fur of the great gerbil and in their colonies, as well as the specific weight per 1 hectare, showed that the general trend in population dynamics tends to decrease. The current epizootic status is considered as inter-epizootic period. The density of great gerbils and their flea populations indicate the presence of conditions conducive to the development of plague epizootics.

The aim of the work was to analyze the monitoring data on contamination of water bodies with Vibrio cholerae О1 during epidemiological surveillance of cholera in Russia.

Materials and methods. The analysis of the data on the isolation of cholera vibrios O1 from water bodies (2015–2024) was carried out using official statistical reports from the Rospotrebnadzor Administrations in the constituent entities of the Russian Federation and anti-plague institutions. Studies of biological properties of the strains were performed in accordance with MR 4.2.3745-22; genome-wide sequencing was conducted on the MiSeg platform (Illumna, USA).

Results and discussion. Information about 848 strains of V. cholerae O1, including V. cholerae O1 ctxА⁺tcpA⁺ (3), V. cholerae O1 ctxA^– tcpA⁺ (48) and V. cholerae O1 ctxA^– tcpA^– (797) in 30 entities of the Russian Federation has been investigated. V. cholerae O1 El Tor ctxA^– tcpА^– and V. cholerae O1 El Tor ctxA^– tcpA⁺ were isolated from 72 water bodies: 46 rivers, 13 ponds, 8 lakes, and other objects in various climatic regions, mainly in the Atlantic-continental European (forest) part, as well as in the continental East Siberian and monsoon Far Eastern areas. The data on contamination of water bodies with V. cholerae O1 in the administrative territories of the Russian Federation, varying by types of epidemic manifestations of cholera, federal districts; sampling points; on the results of epidemiological investigations using genome-wide sequencing of V. cholerae O1 ctxA^– tcpА^– strains are provided in the paper.

The aim of our study was to assess the prevalence of HIV and blood-borne viral hepatitis markers among individuals with post-COVID syndrome.

Materials and methods. The study material consisted of blood plasma samples from 129 patients diagnosed with long COVID. The samples were tested for serological (ELISA with commercial kits, in case of Ag/Ab-HIV detection – Western blot) and molecular (PCR assay) markers.

Results and discussion. Evaluation of overall marker prevalence revealed complex relationships between HIV infection, viral hepatitis, and the development of post-COVID syndrome in the cohort. Our data demonstrate that among HIV-positive patients receiving antiretroviral therapy – who constituted 6.97 % of the study cohort – mild forms of COVID-19 were predominant (55.56 % of cases). This finding aligns with the current understanding of the modulating effect that immunosuppression has on the cytokine storm in case of COVID-19. Furthermore, analysis of the results revealed a higher detection rate of HCV RNA (1.55 %) compared to the general population. This observation warrants further investigation into the potential role of HCV in the development of long COVID, particularly in light of data suggesting prolonged SARS-CoV-2 viremia in this patient category. Conversely, the low prevalence of HB markers (7.75 % anti-HBcore antibodies with no HBsAg-positive cases) did not confirm their association with post-COVID syndrome in our sample, despite literature suggesting increased long COVID risk against chronic hepatitis B. Assessment of blood-borne infection prevalence among COVID-19 survivors may be valuable for early identification of high-risk patients developing post-COVID syndrome. The results emphasize the need for larger-scale studies to clarify pathogenic mechanisms of interaction between chronic viral infections and SARS-CoV-2, as well as to develop personalized monitoring and management approaches for high-risk long COVID patients.

The aim of the work consisted in verification and detailed identification of the causative agent of brucellosis isolated from a patient diagnosed with infectious endocarditis with extensive tricuspid valve damage.

Materials and methods. We investigated the clinical material from the affected person (blood, blood serum) and the obtained culture of brucellosis agent. Medical organization performed tests for sterility of blood using a BC60 hemoculture analyzer. Identification of the grown colonies was carried out on a VITEK® MS mass spectrometer. The Indication Center conducted studies of clinical material samples from the patient and an in-depth study of the Brucella spp. 1079 strain obtained from the medical organization using bacteriological, serological, mass spectrometric, molecular-genetic methods, and high-throughput sequencing.

Results and discussion. The strain, primarily identified as Brucella spp., was isolated from a patient’s blood sample in a laboratory at the medical facility. Following in-depth testing at the Indication Center using a combination of phenotypic and molecular biological methods, this strain was verified and assigned to Brucella melitensis genotype IIi. The culture is sensitive to gentamicin, streptomycin, levofloxacin, doxycycline, rifampicin, amikacin, kanamycin, and tetracycline. It is intermediately resistant to nalidixic acid and ciprofloxacin, and is insensitive to ceftriaxone and trimethoprim-sulfamethoxazole. Nucleotide sequences of the omp25 and omp2a genes of Brucella were detected in blood and serum samples from the patient. These sequences confirmed the presence of B. melitensis in the samples. IgM and IgG antibodies to the causative agent of brucellosis were detected in the patient’s blood serum. As a result of the study, the brucellosis agent isolate obtained at the medical facility from a patient diagnosed with infectious endocarditis with extensive tricuspid valve damage was verified and identified as B. melitensis genotype IIi. This case confirms the need for increased awareness among healthcare personnel regarding particularly dangerous infections, as well as coordinated efforts across various agencies.

The aim of the study was to analyze the data from monitoring cholera prevention measures as part of epidemiological surveillance in the constituent entities of the Russian Federation.

Materials and Methods. An epidemiological and statistical analysis of the data provided by territorial bodies of the Rospotrebnadzor using developed forms was conducted through the departmental information system report.gsen.ru on a weekly basis from April to October in 2023 and 2024.

Results and discussion. In light of the risk of importation and spread of cholera during the period of 2022– 2024, and in accordance with the directives of the Rospotrebnadzor, enhanced monitoring for cholera was implemented across the territory of the Russian Federation. Additional sampling points were introduced at temporary accommodation centers, from wastewater before treatment, from transboundary rivers and other water objects, in cities with population over one million, in port cities, at resorts of the Azov and Black Seas, at wastewater discharge sites from infectious disease hospitals (or departments), and in areas where organized groups of labor migrants live and work. The timing of scheduled monitoring studies was changed in certain territories. The training of specialists was strengthened. The paper presents selected indicators of specialist training, the results of testing for cholera for individuals with symptoms of acute intestinal infections, and the results of monitoring studies on cholera in the territory of the Russian Federation in 2023 and 2024, including the detection of cholera vibrios O1 and non-agglutinating (NAG) vibrios depending on the nature of water use at sampling points, which indicate the presence of conditions for the possible spread of the cholera pathogen by water route in the event of infection importation in 75 % of the country’s entities.

The aim of the work was to detect Orthohantavirus puumalaense (PUUV) reassortant strains in bank voles (Clethrionomys glareolus) of the Republic of Tatarstan (RT), which are closely related to strains previously isolated from patients with hemorrhagic fever with renal syndrome (HFRS) from the RT.

Materials and methods. Viral RNA was detected by RT-PCR in the lung tissue of bank voles captured in the Vysokogorsky and Pestrechinsky districts of the RT in 2023–2024. cDNA was synthesized for RT-PCR-positive samples. PUUV genome fragments of S- and M-segments were amplified using PCR, followed by sequencing (using the Sanger method and Oxford Nanopore technology) and phylogenetic analysis.

Results and discussion. It has been found that 14 PUUV strains detected in bank voles from four capture sites fall into 3 clusters. In two strains from the vicinity of the village of Kinderi (cluster 2), a reassortant genome has been identified: the S-segment is closely related to strains from the Vysokogorsky district (nucleotide sequence (NS) identity is 99.1–100 %), while the M-segment is closely related to strains from the Pestrechinsky district (96.3–97.0 %). These virus strains are genetically close to reassortants previously found in HFRS patients infected by PUUV in the Vysokogorsky district of the RT. Detected in the vicinity of the village Kinderi PUUV strains appear to be of reassortant origin.

Dairy and beef farming is a central agricultural sector in the North Caucasus Federal District. Sick animals are the source of brucellosis infection for humans. In the Kabardino-Balkarian Republic, a region of the North Caucasus with a long-standing epidemiological risk for brucellosis, a cluster (6 individuals) epidemic outbreak of acute brucellosis was recorded in a household in 2024. An epidemiological investigation identified the epidemiological characteristics and presented an etiological explanation for the cluster “family” outbreak.

The aim of the study was to analyze the results of the epidemiological investigation of the group “household” outbreak of acute brucellosis in Kabardino-Balkarian Republic in 2024 and to characterize the features of genome organization of isolated Brucella strains.

Materials and methods. Epidemiological data from the Rospotrebnadzor Administration in the Kabardino-Balkarian Republic were used for the work. We also studied 467 whole-genome sequences, 504 MLVA genotypes of strains from the collection of the Stavropol Anti-Plague Institute of the Rospotrebnadzor.

Results and discussion. Based on the analysis of epidemiological investigation data and molecular-genetic analysis of the isolated strains, the epidemiological and etiological features of a group “family” outbreak of brucellosis were determined. A regional genetic profile of the Brucella population circulating in the North Caucasus has been determined, allowing for differentiation of isolated strains based on the principle of “new” and “rooted” ones. The data obtained from the epidemiological investigation of the family outbreak of brucellosis provide for scientific substantiation of the phylogeny and relationships of brucellosis foci, confirmation of the introduction/importation of the infection to other (previously brucellosis-free) areas, and conducting genomic monitoring of the causative agent of brucellosis.

The aim of the work was to assess the state of natural foci of tularemia, Ixodidae tick-borne borrelioses (ITBB), West Nile fever (WNF), Crimean hemorrhagic fever (CHF) and hemorrhagic fever with renal syndrome (HFRS) in the territories of the Rostov Region, Donetsk and Lugansk People’s Republics as of 2023.

Materials and methods. The study of field material samples, which included 2782 specimens of Ixodidae ticks of six species, 9874 specimens of blood-sucking mosquitoes of 12 species and 2974 specimens of small mammals of 17 species, collected in 2023 in the territories of the Rostov Region, Donetsk and Lugansk People’s Republics, was carried out for the presence of markers of CCHF, WNV, HFRS, Lyme disease, tularemia and leptospirosis pathogens. Infectious agents were indicated using bacteriological, serological and molecular-genetic methods.

Results and discussion. Five tularemia cultures were isolated in the Rostov Region and the presence of tularemia pathogen markers was confirmed (11 positive PCR samples and 15 positive antigen tests), as well as ITBB (12 positive PCR tests), WNF (one positive PCR test and two positive ELISA tests), and CCHF (10 positive PCR tests and five positive ELISA tests). In the Donetsk People’s Republic, markers of tularemia pathogens (six pure cultures, one positive PCR test, and 50 positive antigen tests), ITBB (93 positive PCR tests), leptospirosis (one positive PCR test), WNF (one positive ELISA test), CHF (one positive PCR test and two positive ELISA tests), and HFRS (eight positive ELISA tests) were registered. Markers of tularemia pathogens (one pure culture, 14 positive PCR samples and 49 positive antigen tests), ITBB (65 positive PCR samples), leptospirosis (one positive PCR sample) and HFRS (12 positive ELISA samples) were detected on the territory of the Lugansk People’s Republic. Thus, general structure of parasitic system of active natural foci of infectious diseases, functioning as part of integrated landscape-ecological complex, has been formed in the territory of the Rostov Region, Donetsk and Lugansk People’s Republics.

The aim of the study was to obtain a cholera toxin B-subunit producer based on the avirulent probiotic strain Escherichia coli M-17 and to study its molecular-genetic and immunogenic properties.

Materials and methods. The genetically marked E. coli KS164 thy polA (pIEM3) strain, containing a recombinant plasmid with the cloned ctxB gene encoding the B-subunit of cholera toxin, and the avirulent E. coli M-17 strain, applied for the production of colicontaining probiotics, were used. The strains were analyzed using various methods: molecular genetics, biochemistry, and immunology.

Results and discussion. Through introducing the recombinant cointegrate plasmid pIEM3 (KmRTcR) with the cloned ctxB gene into E. coli M-17 cells via conjugation, KmRTcR transconjugants with high levels of secreted cholera toxin B-subunit production (10 μg/ml) were obtained. One of these transconjugants (KM147) was used as the producer strain for the protective antigen. It was demonstrated that the constructed E. coli strain KM147(pIEM3) KmRTcR stably inherits the cloned ctxB gene contained in the recombinant plasmid, is capable of producing antitoxic antibodies in immunized animals, and safe for the use in model animals. These properties combined make it promising for future use in the development of prophylactic and diagnostic cholera drugs.

The Russian Anti-Plague Institute “Microbe” of the Rospotrebnadzor has a working collection of bacterial viruses with varying lytic activity against microorganisms of pathogenicity groups I–III. Many of them are the matrix of medical products for in vitro diagnostics.

The aim of the work was to bring the working collection of bacteriophages in line with the rules for the creation and use of collections of pathogenic microorganisms and viruses set out in Decree of the Government of the Russian Federation No. 1668 dated September 30, 2021 and in accordance with the requirements of Federal Law No. 492-FZ dated December 30, 2020.

Materials and methods. The study involved the usage of a working collection of bacteriophages specific for PBAs of pathogenicity groups I–III. Collection strains of bacteriophages were lyophilized using protective media with a developed formulation.

Results and discussion. Identification and certification of bacteriophages has been carried out. The procedure of author’s deposition of bacteriophages from the working collection into the State Collection of Pathogenic Bacteria of the Institute “Microbe” has been carried out. The working collection of bacteriophages specific for microorganisms of pathogenicity groups I–III has been brought into compliance with the applicable statutory requirements.

The paper considers the activities of the sanitary-epidemiological service of the Saratov Region during the Great Patriotic War. The relevance of this work stems from the need to understand the historical experience of anti-epidemic protection of the population under extreme wartime conditions and the role of rearward regions in ensuring the country’s sanitary security.

The aim of this work was to analyze the key areas, methods, and results of operation of the sanitary-epidemiological service of the Saratov Region during the war and to assess its contribution to strengthening the home front and preventing epidemics. The work of the sanitary and epidemiological service became a crucial factor in the stability of the rear areas: it preserved the region’s labor potential, ensured the smooth operation of enterprises, and prevented the threat of epidemics among the civilian population and military personnel. The historical experience of the service demonstrates the importance of sanitary-epidemiological measures as an integral part of national security in crisis situations.