The literature review is devoted to the modern concepts of the vesiculation phenomenon and its biological role in pathogenic bacteria – causative agents of particularly dangerous human infections. Data on the production, structure, composition, and functions of the outer membrane vesicles (OMV) of bacteria have been summarized. In recent years, the interest of researchers in the formation of spherical structures (so called bubbles or vesicles) from outer membrane of gram-negative bacteria has significantly increased. Such structures are surrounded by the double layer of a phospholipid membrane, the outer layer of which is enriched with lipopolysaccharide molecules. The inner space of vesicles could include various antigens, receptors, adhesins, toxins, enzymes, porins, etc. The formation of vesicles by the outer membranes of bacteria is recognized as a normal physiological manifestation of bacterial activity aimed at adaptation to environmental conditions. The investigation of the biological role of OMV showed their connection with the pathogenesis and immunogenesis of bacterial diseases. The review provides information on the peculiarity of induction, OMV composition and their participation in the processes of patho- and immunogenesis of severe infections caused by groups I–II PBA – the gram-negative causative agents of plague, tularemia, brucellosis, glanders, melioidosis, cholera, and formation of extracellular vesicles in a gram-positive anthrax pathogen. The particular attention is paid to the issue of developing safe and effective next-generation vaccine preparations based on bacterial vesicles.

The review presents generalized epidemiological data and the situation on infectious diseases requiring measures for the sanitary protection of the territory of the Russian Federation in the countries of the European Region of the World Health Organization (WHO). The epidemiological analysis was carried out using data from the official websites and periodicals of WHO, the WHO European Office, the ministries of health of countries, the European Center for Disease Prevention and Control, other international organizations, as well as materials from publicly available publications. The review summarizes and systematizes data on the incidence and territorial distribution of diseases in each specific country from the standpoint of possible risks for people visiting it. The presented data on infectious diseases make it possible to navigate through issues related to the risk of contracting infectious diseases, to determine the factors and seasonality of an increased risk of infection, and to predict the possibility of importing diseases into the Russian Federation.

For many years, arbovirus infections have been a global health problem and one of the urgent threats to the sanitary and epidemiological well-being of the population. Climatic conditions, species diversity and abundance of vectors, epidemiological and demographic factors are of fundamental importance for the emergence and persistence of natural foci of arbovirus infections. In the Socialist Republic of Vietnam (SRV) and other countries of the Asia-Pacific region, the most complex epidemiological situation is observed in regard to a number of arboviral infectious diseases transmitted by mosquitoes, inter alia to dengue fever. In this review we analyzed the literature data to identify the features of the circulation of some arboviruses in Vietnam, such as dengue virus, Zika, Chikungunya, Japanese encephalitis virus, Dabie virus, and the routes of their transmission and spread. It is shown that the climatic, ecological, epidemiological and demographic conditions existing on the territory of Vietnam contribute to the spread of pathogens of many arboviruses. Areas of more active circulation and ways of spreading pathogens of arbovirus infections have been identified. Based on the data obtained, it is necessary to conduct annual epidemiological and epizootiological survey of the territory of the SRV in order to identify markers of pathogens and determine the boundaries of natural foci of arbovirus infectious diseases which will enhance and increase the effectiveness of preventive and anti-epidemic measures.

Currently, great significance is attached to the preparation of diagnostic drugs based on specific immunoreagents, which include monoclonal antibodies produced by hybridomas. The use of monoclonal antibodies is one of the important approaches for the detection of pathogens of particularly dangerous infections – anthrax, brucellosis, tularemia, plague, cholera, glanders, and melioidosis. The review presents the main achievements of Russian scientists on obtaining such experimental drugs, and also pays attention to those sets of monoclonal reagents that are authorized in the Russian Federation. To date, three sets of reagents for detecting the causative agent of anthrax (latex agglutination, immunochromatographic method, multiplex immunofluorescence analysis) have been registered in our country on the basis of monoclonal antibodies; four sets of reagents for identifying the causative agent of tularemia (latex agglutination, immunochromatographic method, multiplex immunofluorescence analysis, dot-variant of enzyme immunoassay); three sets for the detection of plague microbe (enzyme immunoassay and immune chromatographic tests); five sets for cholera vibrios (slide agglutination, immunofluorescence, immune chromatographic method and enzyme immunoassay); two sets for the diagnosis of glanders and melioidosis (immunofluorescence); kits for detecting brucella have not been registered, there are only singular experimental designs. The involvement of modern drugs based on monoclonal antibodies in the diagnosis of particularly dangerous infections will improve the quality and reliability of laboratory analysis.

The causative agent of plague, Yersinia pestis, is classified as pathogenicity (hazard) group I agent, which means that the work with “wild type” strains should be carried out in BSL-3 facilities. Y. pestis EV NIIEG is a Δpgm strain, allowing experimental studies to be carried out in BSL-2 laboratories. However, the disease and its progression elicited by such strain do not entirely mirror the infection observed with fully virulent strains. Residual virulence of Y. pestis EV NIIEG strain for mice can be increased under in vivo iron supplementation. The aim of the study was to optimize methodological approaches to modeling experimental plague in laboratory animals following administration of attenuated Δpgm Y. pestis strains with iron dextran. Materials and methods. Simulation of plague infection in outbred mice was carried out through subcutaneous inoculation of Y. pestis EV NIIEG strain with iron dextran supplementation. The animal condition was assessed on a daily basis. In the course of the experiment, the pathological presentation and bacterial content in organs of mice were evaluated. Results and discussion. Mice inoculated subcutaneously with Y. pestis EV NIIEG strain in the presence of iron dextran developed a bubonic plague that resulted in lethal outcome with pathological changes of internal organs, characteristic of plague infection. In case of daily administration of iron, LD50 of Y. pestis EV NNIEG strain for the mice significantly exceeded the same one with a single injection. Differences in the survival rate among animals in the groups with a single and multiple administration of iron compared to the control group were statistically valid. Thus, attenuated Δpgm Y. pestis strains in the presence of iron dextran can be used to model experimental plague in mice with marked pathological changes and lethality in BSL-2 laboratories.

The aim of this study was to investigate the current state of vertebrates populations and to determine their role in maintaining natural foci of zoonoses in the Stavropol Territory in 2015–2019. Material and methods. Organ suspensions and blood samples from small mammals and birds were studied using certified diagnostic test-systems for the markers of Crimean hemorrhagic fever, West Nile fever, hemorrhagic fever with renal syndrome, tularemia, and leptospirosis pathogens. The data were statistically processed using Wilson’s method. Results and discussion. Identified have been the main reservoirs of natural-focal infections in the Stavropol Territory at the present stage: birds – for the West Nile fever virus, mammals and birds inhabiting the areas of semi-desert landscape-geographical zone – for Crimean hemorrhagic fever agent. The main natural reservoir of orthohantaviruses in the Stavropol Territory is the common vole Microtus arvalis, which lives in all landscape-geographical zones. The circulation of tularemia and leptospirosis pathogens has been established throughout the whole territory of the region, the small wood mouse Sylvaemus uralensis is of the greatest epizootic significance. Findings indicate the need for further epizootiologic monitoring of Stavropol Territory in order to identify the biocenotic patterns of the pathogens’ existence and the reasons that determine the dynamics of the epizootic process and epidemic manifestations of natural foci. It is advisable to determine the sites of long-term monitoring over the number of carriers and vectors of natural-focal infections and strengthen the epizootiological control over the territory, especially during periods of seasonal activity in carriers and vectors of natural focal infections.

Plague foci differentiation is at the core of surveillance and forecasting of epizootic activity and hence achieving high effectiveness of prophylactic measures for prevention of human plague cases. Improvement of the plague foci differentiation taking into account recent data on their status and functioning is a relevant objective. The aim of the study was to differentiate natural plague foci according to the significance of ecology factors in the dynamics of epizootic activity. Materials and methods. Various models for forecasting epizootic activity of natural plague foci, based on the consistent statistical pattern recognition procedure were applied. 11 plague focal territories for which predictive models had ever been developed were surveyed. Results and discussion. The plague foci differ by impact of biotic and abiotic factors on epizootic activity. If epizootic activity depends on the biotic factors, forecasting can only be made on the basis of the data obtained directly during epizootiological surveillance. If epizootic activity depends on abiotic factors, such plague foci can be more depended on the global climate change. The put forward differentiation of focal areas allows for searching the common patterns of plague epizootic process in foci with different species of hosts and vectors, plague microbe variants and geographic setting, as well as for additional typification alongside the existing ones.

The aim of the study was to analyze the epizootiological and epidemiological situation in the Primorsky Territory (1919–2020) and to zone the administrative districts in regard to anthrax. Materials and methods. Accounting and reporting documents, information and archival materials were collected and analyzed, statistical reference books and literature sources were used. A comprehensive epizootiological and epidemiological survey of 12 supposed places of anthrax burials and cattle burial grounds was carried out, and their biological hazard assessed. Results and discussion. Within the framework of updating the Cadastre of stationary potentially hazardous as regards anthrax areas in the Russian Federation (2005), the number of infected farm animals and human cases was specified: according to official data, over the period of 1930–1979, the disease in 173 animals and 34 people with five deaths was registered in 82 stationary unfavorable for anthrax areas of 22 municipalities of the region. Together with the veterinary service of the region, an audit of 12 supposed places of anthrax burials in seven districts of the region was conducted. Based on the results of a comprehensive epizootiological and epidemiological survey, high biological hazard was established for 2 and potential one – for 1 anthrax burials. The culture of Bacillus anthracis isolated on the territory of Primorsky Territory belongs to one of the canonical SNP clusters – A.Br.008/009 of the global genetic line A (subgroup A1). Five criteria for assessing the epizootiological and epidemiological disadvantage for anthrax and the ranking of indicators of the administrative territories in the region have been determined. Zoning of the administrative territories of the region according to risk of anthrax has been carried out. Prophylactic anti-epizootic and anti-epidemic measures have been put forward.

Tularemia is a zoonotic disease with a wide geographical dissemination, and its causative agent Francisella tularensis can be used as a bioterrorism agent. The aim of the study was to evaluate the use of a set of reagents “Erythrocytic immunoglobulin dry tularemia diagnosticum” (“DET-Ig”) with the help of control test strains and field material from natural tularemia foci. Materials and methods. Using the introduced erythrocyte diagnosticum, we studied the decontaminated cultures of test strains (F. tularensis Miura, F. tularensis 55, F. tularensis Schu, F. tularensis 15 NIIEG, Brucella abortus 544, B. melitensis 16-M, B. suis 1330, and Yersinia enterocolitica 64, Y. enterocolitica 178, Y. enterocolitica 383) and environmental samples suspected of containing F. tularensis. Results and discussion. It has been proven that the developed diagnosticum is specific, sensitive, and easy to use for routine diagnostics of tularemia. In the course of laboratory tests of the experimental series of the DET-Ig reagent kit, the possibility of qualitative determination of the tularemia agent in bacterial cultures, biological material and environmental samples in the reaction of indirect hemagglutination was demonstrated. Comparison of the results of use of erythrocyte diagnosticum in liquid and lyophilized forms showed the advantages of drugs after lyophilization: the possibility of transportation and long-term storage at any temperature conditions in various climatic conditions; the setting of the reaction is possible without the use of special diluents. The guaranteed storage term is set for two years (observation period). The results obtained indicate the prospects of introducing the developed drug into healthcare practice.

A marker of the epidemic significance of Vibrio cholerae is their toxigenicity. Therefore, much attention is currently paid to the creation of diagnostic preparations for the detection of cholera toxin and assessment of the level of its production. The volumetric immunosuspension agglomeration reaction, carried out with the help of latex diagnosticums, is an analogue of the indirect hemagglutination reaction, an affordable and technically simple method, since it does not require special equipment and can be used when conducting research in the field. The aim of the study was to design a polymeric immunoglobulin diagnosticum for determining cholera toxin and the level of its production by vibrio strains. Materials and methods. Cholera toxin was obtained from the producer strain Vibrio cholerae Classical 569 B. Rabbit serum to the toxin was obtained according to the method selected by the authors. A polymeric diagnostic immunoglobulin antitoxic drug was obtained through sensitizing immunoglobulins from cholera antitoxic rabbit serum on the surface of polyacrolein microspheres with a size of (1±0.1) μm. Results and discussion. The analytical sensitivity of the developed diagnostic preparation with control cholera toxin is 100 ng/ml. It detects cholera toxin in toxigenic strains of Vibrio cholerae in a titer of 1:16 – 1:512, gives negative results with non-toxigenic strains of V. cholerae O1, V. Cholerae nonO1/nonO139, with samples of heterologous cultures, LPS preparations, liquid nutrient medium used for the cultivation of V. cholerae. Thus, a polymeric immunoglobulin diagnosticum has been constructed to detect and quantify the production of cholera toxin by vibrio strains, and its analytical sensitivity and specificity have been established.

The aim of the study was to develop a test system that allows for detecting plague pathogen DNA in clinical and biological samples, environmental objects with the simultaneous determination of its appurtenance to the main and non-main subspecies, differentiation of the altai biovar central asiatica subspecies separately. Materials and methods. Primer sets for specific genetic markers have been selected using the VectorNTI 10 software, optimal conditions for PCR were determined for RotorGene devices. To assess the specificity and sensitivity of the developed set of reagents, 44 strains of microorganisms were used, of which 19 were Yersinia pestis strains and 25 strains of heterologous microorganisms. The diagnostic sensitivity of “GenPest-subspecies/Altai-RGF” is 98.6 % with a confidence level of probability of 91 %. The diagnostic specificity of “GenPest-subspecies/Altai-RGF” is ≥ 99 % with a confidence level of 91 %. Results and discussion. A medical product “A set of reagents for the detection and differentiation of plague pathogen strains of the main and non-main subspecies (altai biovar, subspecies central asiatica exclusively) by the polymerase chain reaction with hybridization-fluorescent registration of results in real-time mode (GenPest-subspecies/Altai-RGF)” has been developed. The set of reagents passed the state registration in accordance with the established procedure. The use of the developed set of reagents is relevant for the Gorno-Altai high-mountain plague focus of the Russian Federation and the adjacent part of Mongolia.

The aim of this study was to characterize mutations in the hepatitis B virus (HBV) genome associated with HBsAg-negative form of the disease in patients receiving hemodialysis replacement therapy. Materials and methods. We used blood plasma samples obtained from hemodialysis centers in St. Petersburg, Russia – 173 patients and 108 patients from Belgrade, Republic of Serbia. The samples were examined for the presence of serological (HBsAg, antibodies anti-HBs IgG, anti-HBcore IgG) and molecular-genetic (HBV DNA) markers of HBV followed by whole-genome sequencing and determination of clinically significant virus mutations. Results and discussion. Antibodies to hepatitis B were detected in 7.5 % and 11.1 % of patients from St. Petersburg and Belgrade, respectively. HBsAg was identified only in 1.1 % of cases in the group from Russia and in 0.9 % of cases in the group from Serbia. HBV DNA was determined in 2.8 % of the studied samples from both, patients from Saint-Petersburg and Belgrade. Phylogenetic analysis of 9 viral isolates showed that genotype D virus (88.9 %) prevailed as compared to genotype A (11.1 %) in the examined group. Among the samples obtained from patients from St. Petersburg, four belonged to the D2 sub-genotype, one to the D3 genotype. Four samples obtained from Belgrade patients belonged to different sub-genotypes – D1, D2, D3, A2, respectively. When analyzing the nucleotide sequences of the HBV genomes, mutations in the MHR region were detected in all cases, but only in HBsAg-negative isolates, mutations were revealed in the region of 124–147 amino acids, including mutations P120T, R122K, A128V, Q129R, M133I, G145R affecting the recognition of HBsAg by anti-HBs antibodies and associated with the resistance of the virus to the vaccine. The results of this study indicate that transmission of blood-borne viral hepatitis agent in the hemodialysis departments of the Russian Federation and the Republic of Serbia still exists. The prevalence of the latent chronic hepatitis B, coupled with the presence of vaccine escape mutations in all identified cases, indicates the need to pay close attention to the occurrence of the virus mutant variants in hemodialysis centers.

The aim of this study was to assess the epidemiological and epizootiological situation on tularemia in the Republic of Karelia, and to develop a set of preventive (anti-epidemic) measures. Materials and methods. On the basis of statistical observation data, primary medical documentation and literature data, the morbidity of the population, the number of vaccinated persons, the results of laboratory studies of small mammals, arthropods and environmental objects, the species composition of hosts and vectors of infection were assessed. The situation in the republic was compared to the situation in Finland and neighboring regions of Russia. Results and discussion. The incidence of tularemia was registered in the Republic of Karelia in 1950–1971 (52 cases) and in 2010–2020 (121 cases). In the last decade, mainly the ulceroglandular forms have been diagnosed, the urban population predominated among the patients. In all cases, infection was transmitted through mosquito bites, i. e., not associated with professional activities. There are floodplainswamp and forest types of natural foci in the republic. The results of their monitoring are indicative of the activation of the epizootic process, covering almost the entire territory of Karelia. In several areas bordering tularemia disadvantaged areas of Finland and Russia, a high infection rate of rodents was detected, but tularemia patients were not registered. For an adequate assessment of the situation, it is necessary to increase the efficiency of surveying natural foci, study the immune structure of the population and improve the diagnosis of infection. The main areas of preventive (anti-epidemic) measures are vaccination of persons with professional risk of infection and persons living near the activated micro-foci of infection; reduction of the area of fields not used in agriculture; reclamation work, combating landfills, regular removal of waste from the territories of permanent and temporary residence of the population; the use of effective repellents; raising awareness of the population and authorities about the situation, symptoms of the disease, measures of its prevention.

Objective of the study was to assess the epizootiological and epidemiological situation on anthrax in the Volgograd Region in the period of 1920–2019, to zone the territory according to the degree of disadvantage as regards anthrax using geographic information technologies. Materials and methods. The reporting data of the Rospotrebnadzor Administration, Veterinary Committee in the Volgograd Region, and literature sources were studied. ESRI-ArcGIS 10 software was used as a GIS-platform. Epizootic index was applied in the zoning according to the degree of disadvantage regarding anthrax in the territories of the region. Results and discussion. Currently, 529 stationary potentially hazardous as regards anthrax areas have been registered in 33 districts of the Volgograd Region, 53 anthrax burial sites are accounted for in 20 districts. During the period of 1970–2019, 226 cases of infection of farm animals and 37 cases of anthrax among humans were detected. Most of the stationary potentially hazardous as regards anthrax areas (347 sites, 66 %) were formed in 1930–1949. Maximum activity was observed in 1930–1959. The zoning of the territory of the Volgograd Region was carried out using ESRI-ArcGIS 10 software, as a result of which the municipal districts were divided into four groups according to the degree of disadvantage regarding anthrax. The potential of different soil and landscape zones in the persistence of the anthrax microbe was studied. It has been found that chernozem, chestnut, dark-chestnut soil types, which occupying more than 50 % of the total region area and predominate in the zones of moderately arid and dry steppes, alongside alluvial meadow soils of river valleys, floodplains of rivers are very favorable for the persistence of the anthrax pathogen. The territory of the Volgograd Region is endemic for this infection and epizootiological and epidemiological well-being in the region largely depends on the completeness and timelines of preventive measures. The use of geographic information technologies provides a comprehensive analysis of the infection activity manifestations with reliable improvement of the anti-anthrax surveillance system and control in making differentiated managerial decisions.

The aim of the work was to analyze and assess the results of using PCR test-system “V. cholerae variant ctxB-rtxC FL genes” for identification of Vibrio cholerae O1 with differentiation between typical toxigenic and genetically modified variants in a multiplex format with a real-time hybridization-fluorescent recording of results. Materials and methods. To achieve this goal, a set of reagents for the PCR test-system “V. cholerae O1 variant ctxB-rtxC FL genes”, as well as a method for identifying V. cholerae O1 with differentiation between typical toxigenic and genetically altered variants were utilized. The specificity, specific activity and sensitivity of the developed test-system by the example of 35 V. cholerae O1 strains, 6 V. cholerae non-O1 strains, 5 heterologous strains (Shigella zonnei – 2 strains, one Salmonella typhimurium strain, S. enteritidis, Escherichia coli) were investigated. Results and discussion. The panel of reagents for the PCR test system “V. cholerae variant ctxB-rtxC FL genes” detects DNA fragments of the ctxBCl, ctxBEl, rtxC genes in the genome of toxigenic V. cholerae О1 (has specific activity, analytical sensitivity 1·103 GE/ml) and does not detect these genes in non-toxigenic V. cholerae O1 and non-O1, as well as in heterologous strains of microorganisms (100 % specificity). RF Patent No. 2732448 was granted for the PCR test-system “V. cholerae variant ctxB-rtxC FL genes”. It can be used to increase the efficiency of the epidemiological surveillance system and to carry out a justified scope of anti-epidemic measures in the event of cholera importation into the territory of the Russian Federation.

The Subway is the most important means of transport in Moscow. The active flows of passengers in the metro can contribute to the spread of infectious diseases with airborne and contact mechanisms of transmission, including the coronavirus infection COVID-19. The aim of the study was to assess the level of adherence to the use of personal protective equipment (facial masks, gloves) by passengers of the Moscow Subway. Materials and methods. A prospective study based on a visual assessment of passengers in a rolling stock of the Moscow subway, with division into cohorts of those using masks and gloves (K1), using only masks (K2), using masks in violation of the rules of use (K3) and not using personal protection equipment (K4) was conducted. Observations were carried out during the 42^nd and 43^rd weeks of 2020 in various subway clusters with a division in time into morning, afternoon and evening hours. Additionally, passengers were ranked into groups by occupation during the trip. Statistical processing included the identification of frequencies, their 95 % confidence intervals. To compare the significance of differences in the prevalence of features in paired groups, the methods of 4-field tables (χ2 Pearson) were used. Results and discussion. 18053 observations were validated, covering 61.3 % of stations. Men accounted for 54.7 % (9867). During the observation period, the following shares were established: K1 – 5.2 % (95 % CI 4.9–5.5), K2 – 51.9 % (95 % CI 51.2–52.7), K3 – 26.9 (95 % CI 26.2–27.6), K4 – 16 % (95 % CI 15.4–16.6). The level of adherence to the proper use of PPE is significantly lower among men. Land lines have the lowest proportion of passengers using PPE. Among passengers using electronic devices and paper media, a higher proportion of those wearing masks with violation of the rules of use, compared to passengers without activities, was established. Among passengers using electronic devices, the proportion of those using gloves is the lowest. Within two weeks of follow-up, a significant increase in the frequency of PPE use was revealed.

Objective of the study was to optimize the conditions of submerged recurrent cultivation and the composition of the nutrient medium for obtaining the cell mass of Yersinia pseudotuberculosis strains, used as an adsorbent in the preparation of diagnostic plague immunoglobulins. Materials and methods. We utilized Y. pseudotuberculosis adsorbent strains 6; 31; 68; 69; and 70 belonging to V, I, III, IV, and V serotypes, respectively, received from the State Collection of Pathogenic Bacteria at the premises of the RusRAPI “Microbe”. The cultivation process was carried out on an incubator-shaker, laboratory and pilot fermenters with variation of the process parameters, different options for feeding and nutrient media. Results and discussion. In the course of work, the optimal parameters of recurring submerged cultivation have been established. It was found that the highest biomass yield is provided by a combination of a nutrient medium – a carbon substrate in the form of a broth, based on an enzymatic fibrin hydrolysate, with the addition of galactose as a substrate feeding. Thereat, the morphology and immunochemical properties of microbial cells obtained through modified preparation process do not differ from those produced in the control run. The optimization of the parameters for Y. pseudotuberculosis cell mass cultivation with subsequent upscaling has been performed.

The aim of the study was to create a highly immunogenic vaccine construct based on a recombinant variant of a replication-defective MVA strain of vaccinia virus, expressing virus-like particles that mimic natural infection with Marburg virus. Materials and methods. The recombinant virus was obtained through recombination between homologous viral DNA sequences and the insertion plasmid pDel2-GP-VP-Pat which carries transgenes of the structural proteins GP and VP40 of Marburg virus, flanked by fragments of MVA strain genome. Structure of the recombinant virus was confirmed in PCR and using sequencing, transgenes expression was analyzed by Western blotting, viruslike particles formation was recorded using electron microscopy. Evaluation of immunogenicity and protectivity was carried out using a guinea pig model. The antibody titer was determined in enzyme-linked immunosorbent assay. To assess T-cell response, the intracellular staining of cytokines was used, followed by analysis of samples on a flow cytometer. Results and discussion. On the basis of highly attenuated MVA strain of vaccinia virus a recombinant variant MVA-GP-VP40-MARV has been constructed, carrying a cassette of transgenes, GP and VP40, of Marburg virus in the region of deletion II of the genome. The expression of transgenes in MVA-permissive CER cells infected with recombinant MVA-GP-VP40-MARV strain and secretion of GP and VP40 proteins into culture medium have been demonstrated. Electron microscopy analysis has revealed the presence of Marburg virus-like particles in the culture medium of cells 12 hours after infection. Double vaccination of guinea pigs with MVA-GP-VP40-MARV strain at a dose of 108 PFU/animal induced the formation of antibodies to Marburg and vaccinia viruses, as well as 100 % protection against lethal Marburg virus infection (50 LD50). Using original TEpredict software, the structure of T-helper epitopes of GP protein has been predicted. Using the ICS method, the biological activity of these epitopes has been experimentally confirmed and it was shown that they provide the induction of a T-cell immune response as part of the MVA-GP-VP40-MARV vaccine construct.

Pathogenic hantaviruses, belonging to the family Hantaviridae, genus Orthohantavirus, are widely spread in many regions of the world and cause hemorrhagic fever with renal syndrome (HFRS) in Europe and Asia. In the European Russia, the most active HFRS foci are located in the optimum habitat area of natural reservoir of the Puumala virus (PUUV), bank voles (Myodes glareolus), – in the Middle Volga and Cis-Urals. The largest number of cases of HFRS was registered in the Volga Federal District. In 2019, an outbreak of HFRS was registered among the residents of Saratov and the Saratov Region, the number of cases was 2702. Objective of the study was genetic identification of hantaviruses from HFRS patients and rodent carriers and phylogenetic analysis of full-size genomes from natural hosts during HFRS outbreak in the Saratov Region, 2019. Materials and methods. Blood samples of 8 HFRS patients from Saratov and 3 lung samples of bank voles captured in the suburb of Saratov were analyzed using reverse transcription polymerase chain reaction, followed by sequencing and phylogenetic analysis. Results and discussion. A total of 6 viral RNA isolates from HFRS patients were genetically typed, full-length RNA-isolate genomes were obtained for 3 natural carriers. Our data indicate that PUUV virus was associated with HFRS outbreak in Saratov. Genetic analysis revealed that the virus belonged to RUS lineage of PUUV, related most closely to strains from Udmurtia and Tatarstan and differed from strains circulating in the territory of Bashkortostan and Samara Region.