The review presents an analysis of the epidemiological and epizootiological situation on Crimean-Congo hemorrhagic fever (CCHF) in the Russian Federation in 2021. 49 cases of CCHF were detected in 2021, which is 1.53 times higher than in 2020. The mortality rate was 6.1 %. Sporadic cases of CCHF were registered in the Stavropol Territory, Rostov, Volgograd Regions, the Republics of Dagestan and Kalmykia. The incidence rates of CCHF were below the long-term average annual values in the majority of the constituent entities. Epizootiological survey of stationary observation points has revealed that the number of Hyalomma marginatum imago corresponded to the average long-term indicators in 2021, the peak of H. marginatum activity was noted in the II–III decades of May. The proportion of Ixodidae tick pools positive for Crimean-Congo hemorrhagic fever (CCHF) virus markers exceeded the long-term average indexes in a number of regions. On the territory of the natural focus of CCHF, the circulation of the CCHF virus of the genetic lineages “Europe-1” and “Europe-3” was detected in 2021. Based on the analysis of the epidemiological data of the previous year and natural and climatic factors affecting the abundance and vital activity of H. marginatum ticks, risk-based quantitative forecast for the incidence of CCHF in the Stavropol Territory for 2022 has been compiled.

The paper presents a review of the data on the methods of isolation and control of Vibrio cholerae antigens – cholerogen-anatoxin and O-antigens of Inaba and Ogawa – components of the oral bivalent chemical cholera vaccine produced by the RusRAPI “Microbe”, the only prophylactic drug against cholera registered in the territory of the Russian Federation. Currently, the vaccine is produced using the method of segregated manufacturing of cholerogenanatoxin and O-antigens Inaba and Ogawa with step-by-step control of their main properties, which ensures the production of a high-quality finished product. Ultrafiltration is an effective method for concentrating a semi-finished product, which helps to reduce losses and increases the yield of the final product. It remains promising to develop a method for gentle steril ization of O-antigens to maximize the preservation of specific activity. To control the specific activity of the antigenic components and the finished vaccine preparation, a complex of in vivo and in vitro methods is applied. However, the multi-stage process and duration, the use of several types of laboratory animals, as well as modern WHO requirements determine the need for the introduction of alternative in vitro control methods. The use of cell cultures as a replacement for the biological method appears prospective, and demonstrates a positive correlation with animal tests. To assess the activity of antigens, the use of an immunochemical method – dot-immunoassay with gold nanoparticles – is put forward, which will make it possible to harmonize the control method at all stages of the production process, as well as to determine the serovar specificity of Vibrio cholerae O-antigens. The development of molecular-genetic, microbiological, immunochemical methods is relevant for a more complete and comprehensive control of the main immunogens of industrial strains of cholera vibrio. The introduction of promising methods for obtaining antigens and monitoring their properties will allow for a more complete characterization of the component composition of the finished dosage form of the chemical cholera vaccine.

Live vaccines induce both cellular and humoral immunity and are cheap and easy to use. The induction of immunity is provided through the reproduction of the vaccine strain in the host body without the development of the disease, since the bacterium to which it is necessary to induce the immunity is characterized by reduced virulence (attenuation). The first generation of attenuated strains was chosen from a variety of spontaneous or physically, chemically and biologically induced mutants after virulence assessment. The rapid development of molecular genetics makes it possible to significantly reduce the time of pathogen attenuation via obtaining knockout mutants with genes selected by a researcher or by inserting “avirulence genes” into the genome. But, given that the methodological aspects of the design of avirulent strains are basically clarified, the absence of officially established criteria for assessing the hazard in regulatory documents hinders the determination of the degree of attenuation. In this regard, there is a need for changes in the procedure for accounting and storage of bacterial cultures, as well as regulation of the process of transferring plague pathogen avirulent strains from the 1^st into the 3^rd pathogenicity group for subsequent use in the vaccine preparations development. Thereat, the requirements to methodological aspects of the safe generation of attenuated Yersinia pestis strains and the criteria for testing the virulence loss should be maintained at high levels

The review summarizes literature data on the Vibrio cholerae secretion system of the 6th type. This system is a contact-dependent macromolecular mechanism through which bacteria translocate toxic effector proteins into target cells. It is found in many Gram-negative bacteria, including Vibrio cholerae. V. cholerae infects phagocytic amoebae, nematodes, ciliates, bacteria belonging to different species, as well as unrelated strains of V. cholerae using this system. DNA released after lysis of competing bacteria can be taken up by Vibrio cholerae cells, which leads to the acquisition of new genetic material. The type VI secretion system is involved in the infectious process. The destruction of macrophages and microbiota contributes to the active reproduction of the pathogen and colonization of host epitheliocytes, and the production of effector proteins causes the development of diarrhea and intestinal inflammation. Cholera vibrio secretion system of the 6th type has a structure similar to other gram-negative bacteria. The genes encoding the proteins of this system are located in one large region of the second chromosome and in several additional clusters. It has been shown that toxigenic strains of V. cholerae contain an identical set of secretion system genes, while their composition is variable in non-toxigenic isolates. The regulation of secretion system protein expression differs in V. cholerae strains of different toxigenicity, depends on a number of environmental signals, and is associated with other cell regulatory networks. The paper provides experimental data on the analysis of the structure of the global regulatory gene, vasH, of the type VI secretion system in toxigenic and non-toxigenic V. cholerae O1, biovar El Tor strains isolated in the Russian Federation. Thus, the type VI secretion system is an important mechanism that facilitates the survival of V. cholerae in complex communities in vitro, protects against damaging factors of the macroorganism and increases virulence in vivo, and also provides evolutionary transformations of cholera vibrio. Further study of this system will allow a better understanding of the pathogen-host interaction processes, as well as the adaptation mechanisms of V. cholerae in the external environment.

An analysis of trends in the development of situation on brucellosis in the world over past decade and the data on the main risk factors for the occurrence of epidemiological complications regarding this infection in various regions of the world are provided in the paper. An expert assessment of the current epizootiological and epidemiological situation on brucellosis, the coverage of population and animals with immunization in the Russian Federation is given. Over 9 months of 2021, 210 potentially hazardous as regards brucellosis in cattle areas and 24 sites – as regards brucellosis in small ruminants – were registered in Russia. Compared to the same period in 2020, there was a decrease in the number of newly identified hazardous sites for bovine brucellosis by 35.8 % (117 areas). However, long-term upward trend in epizootiological adversity for bovine brucellosis in Russia persists. The epidemiological situation on brucellosis in the country for the period of 2012–2021 is characterized as unfavorable. Decrease in the number of newly detected human brucellosis cases (by 25.1 % of long-term average values) is observed against the background of persistent unfavorable epizootic conditions for brucellosis among epidemiologically significant species of small ruminants and cattle in regions with developed animal husbandry. In 2021, clusters of human cases were registered in the Republic of Dagestan and Penza Region. In the Republic of Dagestan, against the background of aggravation of epizootiological and epidemiological situation on brucellosis, there was also an alarming trend towards prevalence of a relatively high incidence among minors. The proportion of cases of brucellosis among children under the age of 17 in the Republic amounted to 60.3 % of the total number of minors with newly diagnosed brucellosis in Russia over the past 10 years. Taking into account current epizootic, epidemic situations and the long-term dynamics of the development of situation on  brucellosis in the Russian Federation, the incidence of brucellosis among the population  is predicted to be 10–15 % lower than the average long-term values – 0.18–0.20 per 100000 of the population – in 2022. The number of human cases of brucellosis can range from 250 to 300.

3875 cases of tick-borne borreliosis (TBB) (2.65 per 100000 of population) were recorded in Russia in 2021. Compared to 2020, 61 out of 78 constituent entities experienced a decrease in the incidence rate in 2021. Over the past year, the largest number of cases was registered in the Central Federal District (CFD) – 1797 cases, which is 46.4 % of cases in Russia. Second in the rank by the number of cases of TBB comes the Siberian FD (SFD) – 616 cases (15.9 %), followed by Ural FD – 445 cases (11.5 %), the North-Western FD – 418 (10.8 %), and the Volga FD – 388 (10 %). 134 (3.5 %) and 60 (1.5 % of the total number of cases of TBB) cases were registered in the Far Eastern and Southern Federal Districts, respectively. The last place is occupied by the North Caucasus Federal District (NCFD), where 17 cases were registered, the share of which in the total structure of cases in Russia is 0.4 %. When assessing the long-term dynamics of TBB incidence, a significant trend towards a decrease in the intensity of the epidemic process has been revealed for the North-Western FD, UFD and VFD, as opposed to the CFD and Southern FD, where a significant upward trend was noted. For the Russian Federation on the whole, the Siberian FD, FEFD and NCFD the variation in the incidence rates within the confidence intervals of the long-term annual average values is most likely to be observed in the near future.

The paper presents a description of the epidemiological situation on Hantavirus infection incidence in the countries around the world. Comparative analysis of the intensity and dynamics of the epidemiological process of hemorrhagic fever with renal syndrome (HFRS) in the Russian Federation by Federal Districts in 2021 has been carried out and forecast of the HFRS incidence for 2022 prepared. The study has revealed that tense situation on incidence of hantavirus diseases was observed in the world in 2021. On the territory of the Russian Federation, there was a decrease in the HFRS incidence in 2021 (by 1.7 times compared to 2020). However, the results of epidemiological analysis of the HFRS incidence, epizootiological data and laboratory studies in certain Federal Districts of the Russian Federation indicate that the epidemiological situation on HFRS remains tense. High risk of HFRS infection is predicted in a number of regions of the country due to the favorable natural and climatic conditions in the winter period of 2021–2022 with a heavy snow cover, which contributed to the under-snow reproduction of small mammals, the main carriers of HFRS. The presence of infected rodents testifies to a high likelihood of complication of the epidemiological situation in areas of increased epidemic risk of HFRS.

The aim of the study was to improve epizootiological monitoring and increase the effectiveness of preventive (anti-epidemic) measures for camel plague control in Kazakhstan.

Materials and methods. We used the data on epizootiological and epidemiological monitoring in natural plague foci of Kazakhstan, long-term measurements and indicators for the period of 2000–2020 of the anti-plague and veterinary services of the Republic for the analysis. To process the evidence, epidemiological, epizootiological, microbiological, and statistical research methods, as well as GIS technology were applied.

Results and discussion. The number of camels has increased by 2.2 times in Kazakhstan over the past 20 years.  Where there were 98.2 thousand heads in 2000, it amounted to 216.4 thousand heads in 2020. Over the past 10 years, 152 camels died of unknown causes in the focal area of the country, but laboratory tests for plague turned out negative. According to the hazard criteria, the territory of the country has been conditionally divided into three zones: five regions with a high degree of hazard with a total area of 953.15 sq. km, five regions with medium degree of hazard with a total area of 1230.72 sq. km, and with a low degree of hazard – four regions and three cities of republican significance with a total area of 541.1 sq. km. Constant epizootiological monitoring over plague in camels is a necessity for the system of preventive measures.

One of the key requirements to producer strains used in the manufacturing of immunobiological preparations is their stability, which consists in maintaining the main cultural, morphological, physiological, and productive properties in a series of generations. This paper describes a comprehensive methodological approach to testing strain stability using in vitro techniques.

The purpose of this study was to conduct an integrated analysis of the stability in the strains that produce active components of the chemical cholera vaccine when preparing seed material and at the stage of cultivation.

Materials and methods. Toxigenic strains of Vibrio сholerae 569B of the classical biovar, serovar Inaba and V. сholerae M-41 of the classical biovar, serovar Ogawa were used in the work. Cell morphology was monitored through light and transmission electron microscopy. Atomic force microscopy was applied to measure the main parameters of the bacterial cell. The strains were tested for the presence of ctxA gene in the chromosome using the “GenChol” test system with electrophoretic registration of results. Whole genome sequencing of the strains was performed on the Ion Torrent PGM platform using the Ion 318 Chip Kit and the Ion PGM Hi-Q View Chef 400 Kit. To determine the specific activity of cholera toxin and O-antigen, a DOT immunoassay with a conjugate based on staphylococcal protein A and colloidal gold nanoparticles was applied.

Results and discussion. The stability of the main properties of industrial V. сholerae strains – producers of the active components of the chemical cholera vaccine has been confirmed using microbiological, immunochemical, molecular-genetic methods and microscopic analysis at all stages of cultivation, and the prospects for using the integrated methodological approach experimentally substantiated. Tailoring of these methods will make it possible to control the stability of producer strains, optimize cultivation conditions and, as a result, increase the yield of the necessary antigenic component of the vaccine.

A comprehensive analysis of the accumulated epidemiological and epizootiological data in combination with results from phylogenetic analysis of Yersinia pestis strains creates the basis for establishing patterns of spatialtemporal distribution of the plague pathogen and opens up the prospect of long-term forecasting of natural plague foci activation. Previously, we traced the distribution pathways of Y. pestis, medieval biovar, in the plague foci of the Northern and Northwestern Caspian Sea regions in the 20th and early 21st centuries.

The purpose of this work was to identify the regularities of circulation of Y. pestis, medieval biovar, in four natural plague foci located in the Eastern Caspian Sea region.

Materials and methods. A complex study of the phenotypic and genetic properties of 16 Y. pestis strains isolated in the Ustyurt, Mangyshlak, Karakum and Kopetdag autonomous desert plague foci in 1926–1985 was carried out. They were compared with strains from other natural plague foci in Eastern Europe and Central Asia obtained in 1917–2003. Whole-genome sequencing of 12 of those strains was performed. Phylogenetic analysis included the genomes of other 19 Y. pestis strains that we had sequenced earlier. Based on the 1717 polymorphic nucleotides (SNPs) identified in the core genome, a dendrogram of the relations of the studied strains was constructed.

Results and discussion. All 16 Y. pestis strains from the Ustyurt, Mangyshlak, Kopetdag, and Karakum desert foci belong to the 2.MED1 branch of the medieval biovar. All investigated strains from the first three foci and most of the strains from the Karakum focus are in the Caspian 2.MED1 branch, and three strains from the Karakum desert focus are included in the Central Asian one. We have revealed several waves of dissemination of the strains under the 2.MED1 phylogenetic branch of Y. pestis of the medieval biovar in the Eastern Caspian Sea region in the 20th century.

The purpose of the research was to study the dynamics of residual infectious activity of SARS-CoV-2 virus strains belonging to different genovariants, on different types of surfaces, in samples of drinking dechlorinated water at 24–28 °C, as well as their resistance to disinfectants.

Materials and methods. The studies were carried out using SARS-CoV-2 coronavirus strains obtained from the State Collection of Causative Agents of Viral Infectious Diseases and Rickettsiosis, which operates at the premises of the SSC VB “Vector”. The evaluation of the residual infectivity of the SARS-CoV-2 coronavirus was carried out through titration of samples in cell culture.

Results and discussion. The conducted studies have confirmed the ability of all investigated strains of the SARS-CoV-2 coronavirus to maintain their infectious activity at 24–28 °C on most of the examined types of test surfaces for at least 48 hours, while the virus is best preserved on stainless steel and plastic. All studied strains of the SARS-CoV-2 coronavirus are viable in drinking dechlorinated water for at least 48 hours. In addition, it has been found that all of them are sensitive to disinfectants of different groups, widely used for disinfection when working with pathogenic biological agents or for treating hands and surfaces contaminated with viruses. Chlorine-containing disinfectants are the most active. Skin antiseptics based on ethyl and isopropyl alcohols are suitable for disinfecting hands and objects contaminated with the SARS-CoV-2 virus.

Anthrax poses a pressing issue for veterinary medicine and public health in many countries, including the Russian Federation, which necessitates the improvement and development of new, sensitive and specific diagnostic tools.

The aim of the work was to create an experimental peroxidase conjugate for the detection of specific antibodies to the anthrax pathogen and to optimize the conditions for performing enzyme immunoassay (ELISA).

Materials and methods. The peroxidase conjugate was constructed using horseradish peroxidase and Staphylococcus aureus protein A (Sigma-Aldrich, USA). Bacterial antigens isolated from strains of Bacillus anthracis 55ΔTPA-1Spo, B. anthracis Sterne 34 F2 were used as sensitizing agents. The developed experimental batches of the conjugate were tested in ELISA for the ability to bind antibodies in the blood sera of anthrax patients and vaccinated individuals. The sensitivity, specificity, and accuracy of the method were calculated using the built-in functions of the ROCR software package.

Results and discussion. The peroxidase conjugate to detect specific antibodies to the anthrax pathogen in the study of clinical material has been developed; conditions for the ELISA performance have been optimized. To interpret the results of the study, a threshold value of the positivity coefficient was used, below which the result was considered negative, and at an equal or higher value, positive. The test demonstrated significant differences in the “positivity coefficient” indicator for the “Healthy”/“Sick” and “Healthy”/“Vaccinated” groups, while the differences between the “Sick”/“Vaccinated” groups were statistically insignificant. The maximum accuracy of the method was observed at blood serum dilutions of 1:250 and 1:500. 100 % intra-run, run-to-run and series-to-series reproducibility has been established for all positive samples. The sensitivity and specificity of the experimental peroxidase conjugates were 100 and 95.8 %, respectively, and the accuracy was 97.6 %.

The most common anthropozoonoses on the African continent are coxiellosis and Rift Valley fever. It is known that detection of specific IgG antibodies in the blood sera of farm animals is one of the indicators of the pathogen circulation in a certain territory. 
The aim of the work was to identify specific IgG antibodies in the blood sera of farm animals collected on the territory of the Republic of Guinea to pathogens of zoonotic infectious diseases: coxiellosis, brucellosis, glanders, CCHF, West Nile and Rift Valley fevers, using enzyme immunoassay (ELISA). 
Materials and methods. A panel of 970 samples of blood sera from farm animals inhabiting all landscape-geographical zones of Guinea was compiled for the work. Identification of specific antibodies was carried out using enzyme immunoassay with preparations recommended for veterinary studies. 
Results and discussion. Specific antibodies to zoonoses were detected in 700 out of 1074 samples (65.2 % of the total), including: to Coxiella burnetii – in 172 (16.0 %); to Brucella spp. – in 212 (19.7 %); viruses of Rift Valley fever – 85 (7.9 %); CCHF – in 139 (12.9 %) and West Nile fever – in 92 (8.6 %). Antibodies to Burkholderia mallei were not found in the tested material. Positive samples were registered in all landscape-geographical zones. Thus, an urgent task is to continue studying the circulation of pathogens of zoonoses and anthropozoonoses in the territory of the Republic of Guinea and to organize regular monitoring over the spread of zoonotic infectious diseases in collaboration with veterinary services, which will allow timely forecasting and coordinating prophylactic (anti-epidemic) measures to prevent cases of diseases.

The aim of the study was to develop a methodological approach to determination of Brucella suis biovars through multilocus PCR with real-time registration of results.

Materials and methods. We used 16 strains of B. suis of various biovars, B. neotomae and B. canis – 2 strains of each. Determination of the taxonomic affiliation of Brucella strains was carried out according to the Bruce-ladder, Suis-ladder, BRU-DIF protocols. The selection of primers and probes was performed using the software on the website www.genscript.com and the GeneRanner 6.5.52 program. Fragment sequencing according to Sanger was performed on a 3500 XL genetic analyzer in accordance with the manufacturer’s recommendations. Nucleotide sequence homology was assessed using the BLAST algorithm and the GenBank NCBI database.

Results and discussion. An analysis of the structural organization of IncP and GI-3 genomic islands has been carried out in B. suis strains of various biovars. It has been established that in strains of B. suis II, IV biovars and B. canis, the terminal part of the BRA0368 gene, comprising 21 nucleotides (repeated in the BRA0367 gene) and the “TAA” stop codon, as well as almost the entire sequence of the BRA0367 gene were lost, owing to homologous recombination in the IncP genome island. A 21-nucleotide direct repeat and the “TGA” stop codon of the BRA0367 gene replaced the analogous region of the BRA0368 gene which resulted in the deletion the size of 185 bp. No differences have been noted in the structure of GI-3 in biovars. The evidence obtained made it possible to develop the approach (SuisDIF) for differentiating B. suis biovars, based on the amplification of genes located in the IncP and GI-3 genomic islands using real-time PCR. Its specificity was confirmed in the study of B. suis strains from the fund of the State Collection of Pathogenic Bacteria of the Russian Research Anti-Plague Institute “Microbe”. The conducted studies expand and supplement the data on the genetic heterogeneity of Brucella species and biovars. The proposed method for differentiating biovars of B. suis using multilocus PCR with real-time registration of results enhances the capacities for Brucella identification using molecular-genetic methods.

The aim of the work was to implement the risk management strategies in the manufacturing and use of medical products for in vitro diagnostics by the example of the experimental series of the reagent kit “Lyophilized erythrocyte antigenic tularemia diagnosticum”.

Materials and methods. We tested experimental series of the reagent panel “Lyophilized erythrocyte antigenic tularemia diagnosticum”. To carry out the identification, assessment and analysis of risks regarding the considered medical product, failure mode and effects analysis (FMEA) was proposed and adapted under production conditions. Identification of risks associated with manufacturing and control of medical products for in vitro diagnostics was carried out using technological regulations, standard operational procedures and manufacturing notes.

Results and discussion. The main outcome of the study is the development of a corrective actions system aimed at reducing the risks and ensuring consistent monitoring. The proposed schemes for carrying out the risk management process can be used as standard ones in the design and development of medical products for in vitro diagnostics, taking into account the specifics of each individual manufacturing. The reporting documents developed within the framework of the system are applicable during the inspection of good manufacturing practice and in terms of completing the registration profile of a diagnostic product with subsequent registration in the healthcare system of the Russian Federation.

The aim of the work was information-analytical assessment of the epidemiological situation on infectious diseases that are potentially or truly dangerous in terms of occurrence of emergencies of sanitary-epidemiological nature in the Region of Americas.

Materials and methods. The study was based on the official reports of the WHO, the Pan American Health Organization, the Centers for Disease Control and Prevention, the national Ministries of Health, data from the ProMED information portal, the Global Network for the Epidemiology of Infectious Diseases, and published scientific papers.

Results and discussion. By the model of the Americas, regional epidemiological features have been established, including the endemicity (enzooticity) of territories according to the most relevant nosological forms and the intensity of the epidemic process manifestations. It is shown that the main epidemiological risks in the countries of Central, South America and the Caribbean are associated with dengue, Zika, Chikungunya fevers characterized by a wide territorial dissemination and the ability to cause large-scale epidemic outbreaks, in the countries of North America – West Nile fever. Other infections of international concern include: cholera, that twice caused epidemics of imported origin during the seventh pandemic, which changed the structure of world morbidity; plague, manifested in an annual incidence, including with a complication by the pneumonic form, which determines an increased potential danger of anthropogenic spread; malaria, demonstrating an upward trend in morbidity and the number of intra-continental imported cases; yellow fever, characterized by the activation of natural foci and the expansion of the territories of potential pathogen transmission. The data obtained can serve as a basis for assessing the risks of infectious disease introduction from the American Region into safe territories, improving epidemiological forecasting and validity in making managerial decisions when conducting sanitary and anti-epidemic (preventive) measures.

The aim of the study was to analyze the genetic markers of Lyme disease pathogens, which can be used to specifically indicate maximum number of their strains and isolates.

Materials and methods. The nucleotide sequences of various genes of Borrelia garinii, B. afzelii, B. burgdorferi were downloaded from the NCBI database (National Center for Biological Informatization). The occurrence of the analyzed nucleotide sequences in the genetic code of various organisms was determined in the nBLAST software utility. For the design of primers and probes, the Vector NTI 9.1.0 program (“Invitrogen Corporation”, Carlsbad, USA) was used. DNA was isolated using the MAGNO-sorb kit, version 100-200 (“AmpliSens”, Moscow, Russia), according to the manufacturer’s instructions. Primers and probes were synthesized at “Evrogen” company (Moscow, Russia). For PCR, reagents manufactured by “Synthol” company (Moscow, Russia) were applied.

Results and discussion. In order to perform the reliable indication of pathogenic Borrelia, specific loci (genes) of B. garinii, B. afzelii, B. burgdorferi, which were significantly different from the genetic code of other representatives of the genus Borrelia and from the DNA of other organisms, have been determined by molecular-genetic methods. As a result of a preliminary determination of the analytical significance of the studied loci, the following genes and loci were selected for further work: pepX, clpA, ospA, p83/100, ospC and flaB, of which the flaB and ospA genes were selected for practical indication of pathogenic Borrelia DNA. The genetic markers of B. burgdorferi and B. afzelii are displayed during amplification of the flaB gene, while B. garinii and B. afzelii occur when the ospA gene is used as a genetic marker.

The aim of the work was to evaluate the efficiency of using the “Fhileas 75” hydrogen peroxide vapor generator for decontaminating the air ducts of the individually ventilated system, “Bio A.S.”, for housing of infected animals.

Materials and methods. The hydrogen peroxide vapor generator “Fhileas 75” (France), a disinfectant manufactured by “FHILEASAFE” (7 % hydrogen peroxide solution and 0.15 % peracetic acid solution), separately ventilated system “Bio A.S.” (Germany) for the infected animal housing were applied in the work. Serratia marcescens 9 was used as test-culture.

Results and discussion. The efficiency of using the hydrogen peroxide vapor generator “Fhileas 75” for decontamination of air ducts and internal surfaces of the rack of the individually ventilated system “Bio A.S.” on the test-culture S. marcescens 9 at 1·10⁶ mc/ml concentration has been established (operation parameters of the individually ventilated system unit are as follows: air exchange rate – 60 changes per hour, air flow volume – 28 m³/hour, number of disinfection cycles – 5, disinfectant spraying time – 97 min, exposure time – 24 hours).

The aim – based on the analysis of accidents when working with pathogenic biological agents (PBA) of pathogenicity groups I–II, draw conclusions about the causes of their occurrence and formulate recommendations for improving biological safety measures to reduce the risk of accidents.

Materials and methods. The subject of the study was the data on accidents that happened during the work with PBA, stated in protocols of the commission for monitoring compliance with biological safety requirements of the Volgograd Research Anti-Plague Institute over the period of 1986–2020. Assessed were the type of emergency, their number, main causes and prerequisites for occurrence, professional category of a worker who participated in an accident.

Results and discussion. During the specified period 3 types of accidents were recorded: accidents with spraying, accidents with skin lesion, accidents without spraying. There were no accidents with damage to the insulating suit and the pneumatic suit during the entire period under investigation. Of the total number of accidents, 42.85 % of cases were associated with skin lesion due to the bite of an experimental animal due to its incorrect fixation during infection, feeding, care, or due to autopsy of animals. Spillage accidents were recorded in 42.85 %; accidents without spraying amounted to 14.2 %. The categories of employees who made the greatest number of accidents have been identified: laboratory assistants – 39.2 % of cases, researcher officers – 14.2 %, disinfectors – 14.2 %. The causes of accidents and the prerequisites contributing to their realization have been pinpointed. The main ways and measures to reduce the risks of emergency situations for personnel when working with pathogens of particularly dangerous infectious diseases are put forward.