Objective: To evaluate the historical long-term forecast of the spatial spread of rabies in Siberia and Far East and to characterize modern approaches to spatial forecasting. The concept of spatial spread of rabies in the Asian part of Russia, developed in the 80s of the twentieth century, is subjected to critical analysis based on information on rabies registration for 1881–1980 and zoogeographic data. At that time, 5 rabies enzootic regions were identified, and the most probable directions of further exportation of infection suggested. At first, a review of published data on human and animal rabies cases for the period of 1985–2019 was undertaken (including reference publications). Data on cases of rabies among humans and animals were selected for which geographical coordinates could be determined. Mapping was performed using GIS (QGIS 3.12.0 software and “Natural Earth” and “OpenStreetMap” electronic maps). Comparison of maps for different time periods demonstrated that rabies incidence was recorded mainly within the previously identified risk areas. However, the occurrence of human disease in different regions did not always correspond to the intensity of epizootics and the predicted risk. Next, in an attempt to correct the prognosis of the spatiotemporal rabies spread, we reviewed publications that incorporated virus genetic data along with GIS technology and modeling application. The distribution of the three major rabies virus lineages (“steppe”, “Arctiс-like”, “Arctic”) corresponded to the regions that were previously identified. The spread of fox rabies (the “steppe” rabies virus lineage) in the north-east direction was described. In several instances, rabies outbreaks in southern Siberia and Far East were associated with cross-border movement of the virus from Kazakhstan, Mongolia and China. Data on the speed of the epizootic waves, pathways, and natural barriers for virus spread are discussed. The correction of the forecast for rabies virus circulation and spread is important for the development of control strategies in the region, including oral vaccination of wildlife virus reservoirs.

Dangerous viral infectious diseases pose a serious threat to human life and health, as their uncontrolled spread leads to the development of major outbreaks and epidemics. Rapid and accurate detection of the pathogen is an essential component of the fight against infectious diseases. This review is devoted to loop-mediated isothermal amplification (LAMP), which is one of the simplest and most reliable methods of molecular-genetic research that meets modern requirements. The simplicity of the analysis and registration of the obtained results, which is necessary under conditions with minimal laboratory capacities, makes it possible to consider this type of diagnostic technology as the most promising, which allows us to identify genetic markers (DNA or RNA) of pathogens of dangerous infectious diseases in the shortest possible time. Objective of the review is to summarize and systematize the data available to date on the use of LAMP for detecting RNA of dangerous infectious diseases caused by the Ebola,Marburg and Lassa viruses. The paper discusses the basic principles of the loop isothermal amplification reaction, the components that make up the reaction mixture and are used for the analysis, as well as methods for detecting the results obtained. When studying the information available in the literature sources about the advantages and disadvantages of LAMP, it is shown that in many cases, isothermal amplification is not inferior in sensitivity and specificity to the main molecular-genetic diagnostic methods currently used. Modifications that can be used for accelerated diagnostics of RNA-containing viruses are also considered.

This review describes the current situation on highly pathogenic avian influenza virus in 2019 and predicts the possible further spread of avian influenza in Russia. In 2019 outbreaks were reported among wild birds and poultry, as well as human infections with influenza viruses of the subtypes H5Nx, H7N9 and H9N2 in several countries. In 2019, only two outbreaks of highly pathogenic avian influenza H5N8 in Russia occurred. Both outbreaks were recorded in January at poultry farm in the Rostov Region. In addition, in May 2019 avian influenza virus of H14N7 subtype was isolated from a wild bird during the avian influenza virus surveillance in Tomsk Region. In June 2019, a strain of H13N2 subtype was isolated in the territory of Kamchatka Region, then, in August 2019, an influenza virus of H13N6 subtype was isolated in the Saratov Region. It was revealed that some strains of avian influenza virus isolated in Russia have a high degree of identity with strains circulating in South-East Asia. This was shown by the phylogenetic analysis of A/ H5Nx influenza viruses previously isolated in the Saratov Region and the Socialist Republic of Vietnam during the avian influenza virus surveillance. Thus, it was demonstrated again that the territory of Russia plays a key geographical role in the global spread of avian influenza virus.

Objective of the study was to monitor the spread of cholera in the world, in the CIS countries and in Russia with an assessment of risks and emergencies that contribute to the activation of the epidemic process. Despite the downward trend in the global incidence rate of cholera during the period between 2010 and 2019, epidemics and major outbreaks occurred in 96 countries. WHO has reported 2013 imported cases of cholera to countries in Asia, the Americas, including the Caribbean, Europe, and Australia with Oceania; cholera-endemic administrative territories are identified in 24 countries. According to WHO, cholera burden reduction in Asia and Africa is associated with large-scale vaccination. During epidemiological surveillance of cholera, 705 strains of V. cholerae O1 and O139 serogroups were isolated from surface reservoirs in 26 constituent entities of the Russian Federation, including 10 strains of V. cholerae O1 ctxA+tcpA+, 35 strains of V. cholerae O1 ctxA^–tcpA⁺, 655 strains of V. cholerae O1 ctxA^–tcpA^– , and five strains of V. cholerae O139 ctxA^–tcpA^–. Identification of strains with unique, previously unknown INDEL genotypes testifies to their imported nature. The forecast for cholera in the world for 2020, given the proven high degree of epidemic process activation at the expense of social and environmental risks caused by emergencies of different origin, the presence of endemic foci, infection import and other risk factors is unfavorable. For Russia, the forecast for cholera will be determined by the presence of external risks created by the ongoing 7-th pandemic, possible importation of infection to constituent entities of the Russian Federation that differ by the types of epidemic manifestations.

The paper presents the data on brucellosis incidence in a number of countries around the world. An assessment of the epizootic and epidemic situation of brucellosis in the Russian Federation in 2019 is performed. In 2019, Russia maintains the presence of an unfavorable epizootic situation for brucellosis. An increase in the number of brucellosis infected cattle by 14 % and primary foci of small cattle infection by 52 % was established. Epizootics of bovine brucellosis were mainly recorded in the North Caucasus (63.5 %), Southern (19.9 %) and Volga federal districts (7.4 %). The main number of points unfavorable for brucellosis of small cattle, and sick sheep and goats were detected in two federal districts – North-Caucasian (36.8 %) and Southern (26.3 %). The epidemic manifestations of brucellosis in the Russian Federation are closely related to the activity of the epizootic process among the main epidemiologically significant species of farm animals. In 2019, Russia registered 397 human brucellosis cases (0.27 0/₀₀₀₀ including 23 (0.08 ⁰/₀₀₀₀ among minors. The number of cases of brucellosis and the value of the incidence rate in 2019 are comparable with long-term average data over the past 10 years. The largest number of human brucellosis cases, as in previous years, was established in the North-Western Federal District (278 cases, 70.4 % of the total number of cases) and the Southern Federal District (59 cases, 14.9 %). There is an increase in the relative long-term incidence of brucellosis in the Republic of Dagestan, Voronezh, Penza Regions and the Republic of Kalmykia. In the territories of these subjects in 2019, atense epizootic situation regarding brucellosis among cattle and small cattle was noted. Taking into account the current epizootic and epidemic situation and the long-term dynamics of brucellosis situation development in the Russian Federation, in 2020 it is possible to predict human brucellosis incidence at the level of 0.23–0.27 ⁰/₀₀₀₀.

The results of the analysis of epidemiological and epizootiological situation on anthrax in the Russian Federation and in the world in 2019 are presented in the paper. The forecast of morbidity rates in the Russian Federation for 2020 is made. In 2019, five cases of cutaneous anthrax were registered in the Russian Federation in two regions of the North Caucasian Federal District – Republic of Dagestan (4) and Stavropol Territory (1), which is two cases plus as compared to 2018. Outbreaks of infection among livestock animals and humans were recorded in such neighboring countries as Azerbaijan, Armenia, Belarus, Kazakhstan, Kyrgyzstan and Tajikistan. The unfavorable epizootiological situation on anthrax was observed almost everywhere. The highest incidence rates among wild and livestock animals were found in a number of countries in Asia and Africa. Anthrax among people was registered mainly in African countries, infection occurred mainly by alimentary route, less often – through contact with carcasses, meat of animals. Anthrax morbidity rates among animals and humans in the Russian Federation in 2020 will be largely determined by the completeness of registration and coverage with specific immunization of livestock animals and groups of people under professional risk of infection and, if measures are fully implemented, incidence will not exceed single cases.

Objective of the review is to characterize the nature of epidemiological situation on HFRS around the world and to conduct a comparative analysis of intensity and dynamics of the epidemiological process in the Russian Federation by Federal Districts, as well as make forecast for 2020. The analysis of the epidemiological situation is based on the materials of the official websites of healthcare organizations in the USA and Europe, WHO, the data from operational monitoring carried out by the reference center for HFRS monitoring “Kazan Research Institute of Epidemiology and Microbiology”, materials provided by the Rospotrebnadzor Institutions in the constituent entities of the Russian Federation. The analysis included all administrative territories of the Russian Federation. Statistical processing was carried out by standard methods of variation statistics applying Excel software. The epidemiological situation on hemorrhagic fever with renal syndrome around the world and in Russia remains tense. In the Russian Federation, epidemically active foci are located in the European part of the country, in Western Siberia and in the Far East. Infections over the period of 2010–2019 were registered in 8 federal districts of the Russian Federation, in 58 constituent entities. However, the incidence distribution across the territory of the country was differential. In 97 % of the cases, the incidence was recorded in the European part of Russia. In the Volga Federal District, HFRS incidence amounted to 82.16 % of the total incidence recorded on the whole in Russia. High incidence rates are also recorded in the Central Federal District (CFD). Over the past 10 years (2010–2019), there has been an increase in the incidence of HFRS in the Central and North-West Federal Districts, and a decrease in the incidence in the Ural and Far Eastern Federal Districts. Varying degree of anthropogenic impact on the natural HFRS foci and climate change manifested in increased ambient air temperatures are of great importance for the spread of HFRS over the past decade. At the end of the review the forecast of the development of the epidemiological situation on HFRS in the Russian Federation for 2020 is presented.

Abstract. Objective of the work was to conduct a comparative assessment of the immune-modulating effect of the combined use of Yersinia pestis EV NIIEG vaccine strain with Polyoxidonium and Ingaron preparations on a BALB/c mouse model.

Materials and methods. Mice of the BALB/c line were immunized subcutaneously with Yersinia pestis EV NIIEG culture at a dose of 2.5 10⁴ m.c. (1st group), in combination with Ingaron at a dose of 150 IU (2nd group) or with Polyoxidonium at a dose of 4 мg (3rd group), the 4th group is intact mice. On days 3, 7, 21 and 90 after immunization, the subpopulation composition of lymphocytes, the production of mediators of the cellular response (INF-ɣ and IL-10), the titers of specific antibodies to the capsular antigen of plague microbe (F1), the nuclear apparatus of lymphocytes, and the nature of histological changes in the organs of mice were determined. Characterization of immunogenic (protective) activity of the combined use of Y. pestis EV NIIEG with immune-modulators against Y. pestis 231 in experiments on BALB/c mice was performed on the 21st day after immunization through determining the number of dead animals and their average life expectancy.

Results and discussion. The combined administration of Y. pestis EV NIIEG vaccine strain with Polyoxidonium or Ingaron to experimental animals allowed us to establish differences in the response of the immune system of biomodels, due to the mechanism of action of a specific immune-modulator. It has been established that both Polyoxidonium and Ingaron combined with Y. pestis EV NIIEG enhance the response of immune-competent cells in experimental animals, contribute to the activation of the humoral response and the production of mediators of the cellular response, do not have a damaging effect on the tissue of the macroorganism. At the same time, the efficacy of using combined vaccination of Y. pestis EV NIIEG with immune-modulators in the inoculation test is confirmed for Polyoxidonium only.

Objective of the study was to identify epidemiological peculiarities of HFRS outbreak in the territory of the Saratov Region in 2019 and to determine the key factors contributing to the intensity of epidemic process.

Materials and methods. Analyzed are the data on 2702 cases of HFRS registered in the territory of the Saratov Region in 2019, obtained from the Rospotrebnadzor Administration in the Saratov Region and Center of Hygiene and Epidemiology in the Saratov Region. The basic method of investigation was epidemiological one with application of advanced information technologies.

Results and discussion. Retrospective analysis of epidemic HFRS manifestations in the Saratov Region showed that HFRS outbreak of 2019 was the largest over the period of disease reporting, both by the number of cases (2702) and by the duration. Early onset of increase in the incidence (may) and allocation of the majority of cases to the territory of the natural park “Kumysnaya Polyana”(75 %) should be considered as characteristic features of the outbreak. We have conducted epidemiological zoning of the Saratov Region allowing for dividing the Region into four types of territories which differ by the level of risk of HFRS exposure (very high, high, medium, and low), as well as distinguishing the most hazardous in terms of HFRS infection territories of Saratov. The key factors affecting the surge in HFRS cases were high numbers of infected rodents during spring months of 2019 due to mild and extremely snowy winter of 2018–2019; reduction in forest engineering works aimed at turning the focal territory into aesthetic forestry. The change in the character of exploitation of 9 % of the natural park “Kumysnaya Polyana” resulted in the increase of population contacts with natural-focal complexes. Mass visits to natural focus during early spring period against the background of low alertness to risks of HFRS infection led to explosive growth of HFRS incidence.

HtpG (high-temperature protein G) is a bacterial homologue of the highly conserved molecular chaperone Hsp90 of eukaryotes, which plays an important role in protection against stress in many bacterial species. The role of the htpG gene encoding the synthesis of high-temperature prokaryotic G protein in the pathogenesis of bacterial infections is still unclear.

The aim of this work is to study the functional importance of HtpG in the pathogenesis of plague.

Materials and methods. Isogenic Yersinia pestis sets based on attenuated and virulent strains differing in the presence of the functional htpG gene (YPO3119) were generated with the help of site-directed mutagenesis. The HtpG amino acid sequence was analyzed using the BLAST program. The properties of the resulting mutant strains were evaluated using microbiological and biological methods.

Results and discussion. The bioinformatics analysis showed high conservativeness of the HtpG protein within the Y. pestis species (100% identity), as well as 99 % identity with the Y. pseudotuberculosis protein and 96 % identity – Y. enterocolitica protein. Y. pestis htpG knock-out mutants showed increase of susceptibility to temperature and oxidative stress like mutants of the other bacterial species. However, the mutant was not sensitive to osmotic stress and human serum complement. The loss of the ability to synthesize HtpG by plague microbe did not affect the virulence and average life duration of mice and guinea pigs challenged subcutaneously. It means that htpG gene is not a good molecular target for the treatment and/or immunoprophylaxis of plague.

Objective of the study was to conduct whole-genome sequencing of the vaccine strain Francisella tularensis 15 NIIEG and determine, based on the results, its phylogenetic relationships and the genetic organization features.

Materials and methods. Whole-genome sequencing of F. tularensis 15 NIIEG strain was performed on Ion PGM (Ion Torrent, USA) and MinIon (Oxford Nanopore Technologies, UK) platforms. Alignment of readings obtained to the whole-genome of F. tularensis subsp. holarctica LVS (CP009694, USA, 2015) was performed using the software package DNASTAR Lasergene 15.3. Hybrid assembly of reads into contigs was performed by means of Unicycler v. 0.4.4, using data obtained by semiconductor sequencing technology (Ion PGM) and nanopore sequencing (MinIon). Phylogenetic analysis was performed on the basis of single nucleotide polymorphism (SNPs) data located in the core part of F. tularensis genome. Maximum parsimony algorithm was used to construct a dendrogram using the obtained data of common SNP-matrix.

Results and discussion. The close relations of F. tularensis 15 NIIEG strain with F. tularensis LVS vaccine strain used in the countries of Western Europe and North America was confirmed. Searching for common single mutations characteristic of F. tularensis 15 vaccine strains of NIIEG and LVS, permitted to find 5 unique SNPs that distinguish them from all other 228 F. tularensis strains used in the comparison. Comparative genomic analysis ofF. tularensis 15 NIIEG vaccine strain and virulent strains revealed in its structure two extensive 526 bp deletions (genes pilA and pilE) and 1480 bp (genes encoding lipoprotein). Similar deletions are also present in the genome of the F. tularensis LVS vaccine strain.

Objective of the work was to identify molecular-genetic peculiarities, to conduct whole genome sequencing and phylogenetic analysis of Yersinia pestis strains isolated inVietnam between 1962 and 1989.

Materials and methods. We have studied the properties of 50 Y. pestis strains, carried out whole genome sequencing of 18 and fragment sequencing of 32 strains from Vietnam. Phylogenetic analysis was performed on the basis of whole genome SNPanalysis by 1391 identified SNPs. Whole genome SNP-analysis and search for marker SNPs were conducted applying Wombac 2.0 software package. Phylogenetic diagram construction was done using Maximum Likelihood algorithm.

Results and discussion. Several phylogenetic branches and Y. pestis populations coinciding with geographical and historical dissemination of the strains have been distinguished. The major part of the strains from Vietnam falls under the branch designated by us as 1.ORI2v. Two strains form a separate branch together with the strain from India belonging to 1.ORI2 line, one more strain, 55-801 Saigon, is set among the strains of 1.ORI1 line. Based on the data obtained and evidence from the literature sources it can be assumed that introduction of plague into Vietnam occurred through several waves: Nha Trang city in 1898, by sea; north provinces of the country – 1908. The second wave of Y. pestis dissemination across the territory of Vietnam began in 1960s with the emergence of the strains from the natural plague focus in Yunnan province, China.

Objective of the study was to differentiate the Administrative Districts of theTransbaikalTerritory at the time of Tick-borne viral encephalitis (TBVE) incidence recession by epidemiological risk groups and to characterize them by volume of specific and nonspecific preventive measures.

Materials and methods. Retrospective analysis of TBVE epidemiological situation is based on the statistical reporting data “Information on infectious and parasitic diseases” in 2009–2019 and other materials of the Rospotrebnadzor Administration in the Transbaikal Territory. The clustering of areas with various levels of epidemiological risk was conducted by calculation of 95 % confidential interval for long-term annual average of TBVE cases in municipal units of the Territory over a decade and assessment of appurtenance of the deviating values to the aggregate under study.

Results and discussion. Twenty four out of 32 districts of the Transbaikal Territory are endemic for TBVE. These areas are divided into five groups: with very high epidemiological risk (2 districts), high (5), medium (8), and low (8) risk respectively, as well as the administrative center of the constituent entity which by the whole complex of indicators (disease manifestation, population density, factors of targeted TBVE decrease, social-and-living and economical conditions) cannot be considered together with the rest of municipalities. Each group of the districts was characterized by the number of cases and TBVE incidence rates, medical aid seeking by persons who suffered from tick bites, vaccination volumes, seroprevention, areas of acaricide treatments. Recommendations are presented for the essential complex and scope of measures to prevent TBVE in the groups of administrative districts that differ by the level of epidemiological risk.

Objective. Construction of positive control samples based on recombinant retroviral particles and their application in RT-PCR diagnostic assays for RNA detection of agents of dangerous and particularly dangerous viral infections.

Materials and methods. Molecular biological, genetic engineering, and immunological methods were used: polymerase chain reaction, restriction, ligation, cloning, transformation, transfection, flow cytometry.

Results and discussion. Technology of positive control samples producing based on recombinant virions has been developed and tested. It includes construction of retroviral vector with cloned diagnostic sequence of the viral genome; obtaining a packaging cell line producing chimeric retroviral particles; determination of recombinant virions titer by flow cytometry and polymerase chain reaction; application of the obtained preparation as a control sample for PCR diagnostics of infectious agents. Positive controls based on retroviral vectors as carriers of genomic RNA fragments of pathogenic viruses were used in the development of PCR diagnostic kits for dangerous and particularly dangerous viral infections. Their application increased the kits quality and made it possible to exclude the work with concentrated hazardous infectious agents (Lassa virus, tick-borne encephalitis virus, lymphocytic choriomeningitis virus, Puumala virus).

Objective of the study is to analyze the genetic markers of tick-borne encephalitis virus, which can be used to specifically indicate the maximum number of virus strains and isolates.

Materials and methods. Plasmid DNA and nucleic acids of the tick, the genus Ixodes and Dermacentor, were used as amplified material. Polymerase chain reaction (PCR) was conducted on C1000 amplifier with a CFX96 optical unit (BioRad). The species (strain) variety of detected organisms, using the analyzed genetic markers, was determined in the nBLAST software utility. The design of the nucleotide sequences of primers and probes was performed using “Vector NTI 9.1.0” (Invitrogen Corporation). Nucleic acids were isolated by magnetic sorption with a reagent panel MAGNO-sorb. Primers and probes were synthesized at “Evrogen” company, Moscow, Russia. The reagents for PCR were manufactured by “Syntol” company, Moscow, Russia.

Results and discussion. When indicating the genome of the tick-borne encephalitis virus, the main criterion for choosing a marker sequence is the specific detection of nucleic acids of only the desired microorganism. The genomewide nucleotide sequences of various strains and isolates of tick-borne encephalitis virus were analyzed to search for a specific marker nucleotide sequence. Mutual comparison of all the above mentioned genomes made it possible to determine 7 conventionally conservative loci characterized by minimal nucleotide variability. The further work was based on the results of alignment of the nucleotide sequences of tick-borne encephalitis virus isolates, including the nucleotide sequences of heterogeneous microorganisms; primers and probes were designed to amplify each of the marker loci; the most analytically significant oligonucleotides were developed based on loci 4 and 7. Amplification with oligonucleotide primers to indicate tick-borne encephalitis virus was effective, both in a separate PCR with a positive control, and in combination with tick DNA.

Objective of the study was to assess the current epizootic settings along the border part of KharkhiraTurgensky natural plague focus betweenRussia andMongolia.

Materials and methods. Epizootiological survey covered 2715.5 km2. 213 samples of field material were tested (90 specimens of mammals, 102 specimens of ectoparasites, 17 samples of leftover food of predatory birds and dry skeletal remnants of marmots, 4 regurgitates of birds of prey). Laboratory works were carried out in “Microbiological laboratory for express diagnostics” mounted on the platform of the minibus “GAZelle”. Tests of field material were performed using immune-chromatographic (IC) assay and polymerase chain reaction (PCR). PCR and IC positive samples were further investigated applying bacteriological method. Epizootiological surveyed deployed GIS instruments. All the results obtained were plotted on the electronic maps using QGIS 2.18.26 software.

Results and discussion. Capsular antigen (F1) of Yersinia pestis was detected in three (1.4 %) studied samples (n=213), DNA of plague microbe – in eight samples (3.7 %). Bacteriological investigation of positive samples revealed one sample (leftover food of predatory birds – Mongolian marmot) from which plague agent culture was isolated. The culture belonged to Y. pestis of the main subspecies. Geographical positioning of the epizootiological survey sites was conducted, as well as positive findings of immunological and molecular-genetic assays. Results of epizootiological survey are indicative of active phase of plague agent circulation (main subspecies) in Kharkhira-Turgensky natural focus in Mongolia.

Abstract. Detection of epidemiologically significant mosquitoes Ae. аlbopictus in the south of Russia (the Greater Sochi region, the Black Sea coast of Caucasus) suggested the possibility of their introduction into Crimea.

Objective was to determine the possibility of existence of epidemically significant vector – mosquito Ae. albopictus inCrimea.

Materials and methods. Within the frames of entomological monitoring, mosquitoes were collected during May-October, 2018 and May-September, 2019 in different regions of Crimea: Bakhchisaray, Dzhankoy, Razdolnensky, Saksky, Black Sea regions, urban areas ofSimferopol,Sevastopol and Feodosiya. Fully-grown mosquitoes were caught by automatic trap Mosquito Magnet Executive (USA) with octenol-based bait. Actively attacking females were collected with an aspirator by Gutsevich method. The survey was conducted in the evening and night hours. A total of 26 visits were made, 77 hours were spent, and 8463 mosquitoes (adult and larvae) were captured.

Results and discussion. During entomological monitoring of the territory of Crimean Peninsula for the first time bloodsucking mosquitoes Aedes (Stegomyia) albopictus (Skuse, 1895) were found. Given the favorable climatic conditions in Crimea, the trend towards global warming, the adaptation of mosquitoes to the periods of cold, biology of Aedes albopictus, the distribution of this species in the European part of southern Russia, the formation and dissemination of sustainably replicating vector population on the Crimea Peninsula is possible. To confirm the circulation of independent Ae. albopictus population inCrimea, not a random import of adult specimens who die in winter, further entomological surveys are required on a regular basis.

The paper contains the data on epidemiological situation on COVID-19 in the Republic of Uzbekistan. As of June 29, 2020, 8031 laboratory confirmed cases of COVID-19 were registered across the country; 22 cases with lethal outcome. The paper describes the national policy in the prevention of importation of this infection into the territory of Uzbekistan and halting further spread among the population. Complex measures in response to the transmission of COVID-10 are specified. The paper defines support activities provided for the partner countries by the Republic of Uzbekistan to control COVID-19 pandemic.

Abstract. Objective of the study was to develop an effective method of sample pooling for the detection of SARSCoV-2 coronavirus RNA using PCR and evaluate that approach with various test systems.

Materials and methods. SARS-CoV-2 coronavirus RNA was detected in samples containing nasal swabs placed in a transport medium. 5 samples were combined into one pool to perform the analysis. The effectiveness of the “in single test tube” pooling method for performing mass studies for COVID-19 was evaluated using the Vector-PCRrv-2019-nCoV-RG-19 test systems,Russia; “ArtTest COVID-19”,Belarus; “BioSpeedy”,Turkey.

Results and discussion. A total of 587 pools were studied, consisting of 2935 test samples, in which 56 samples containing SARS-CoV-2 RNA were detected and confirmed by PCR. When studying the method of pooling samples, its specificity and optimal sensitivity for detecting SARS-CoV-2 RNA using the Vector-PCRrv-2019-nCoV-RG, ArtTest COVID-19, and BioSpeedy test systems were shown. The results of applying the pooling method correlated with the data obtained without pooling samples. The average deviation of the cycle amounted to 2 Ct; the fluorescence curve of positive samples corresponded to the «S» form.