Introduction. The surveillance of influenza viruses in ARVI structure and study of their properties in epidemic season 2019–2020 in Russian Federation are actual for investigations due to tasks of Global Influenza Strategy initiated by WHO in 2019.Material and methods. The data of epidemiological surveillance on influenza- and ARVI-associated morbidity and hospitalization in different age groups of population were analyzed; virological, genetic and statistical methods were used.Results. Preschool children were involved in epidemic the most. Meanwhile, the highest rate of hospitalization was observed in patients of 18–40 years old. Influenza A(H1N1)pdm09 virus dominated in etiology of ARVI in hospitalized patients and pneumonia. The role of respiratory viruses in severe cases of pneumonia and bronchoalveolar syndrome in children was shown. The differences in spectrum of circulating viruses caused ARVI in different regions of Russia were found. Influenza A(H1N1)pdm09 and B/Victoria-like viruses were the main etiological agents that caused of epidemic; its activity among all ARVI was 7.3 and 8.0%, respectively. The differences in antigenic properties of influenza A(H3N2) and B epidemic strains compared to vaccine viruses were found. The populations of epidemic strains were presented by following dominant genetic groups: 6B1.A5/183P for A(H1N1)pdm09, 3С.2а1b+137F for A(H3N2) and V1A.3 line B/Victoria-like for B viruses. The good profile of epidemic strains susceptibility to anti-neuraminidase inhibitors has been saved. The most of the studied influenza strains had the receptor specificity characteristic of human influenza viruses.Conclusions. Obtained results identified the peculiarities of viruses caused the influenza and ARVI in epidemic season 2019–2020 in different regions of Russia. These results suggested the important role of influenza A(H1N1) pdm09 in severe cases and pneumonia in adults 18–40 years old. The continuing drift in influenza viruses was found, which, apparently, could not but affect the efficacy of vaccine prophylaxis and was also considered in the recommendations of WHO experts on the composition of influenza vaccines for the countries of the Northern Hemisphere in the 2020–2021 season.
Twenty years ago in the South Chinese province of Guangdong the epizooty of highly pathogenic avian influenza (HPAI) H5N1 virus, which has laid the foundation of the largest epizooty in the contemporary history, has flashed. Hemagglutinin of prototype A/goose/Guangdong/1/1996 (H5N1) changing many times and generating new genetic subgroups participated in various reassortations; it still exists today. The present review is devoted to the retrospective analysis of HPAI/H5N1evolution for the last twenty years in the territory of Eurasia, Africa and America. The basis for the discussion is ecological model according to which new genetic variants are formed in the migration pathways with close contacts between different bird populations and in the overwintering areas where the maximum values of the immune layer occur; amplification of virus variants occurs in nesting areas among juvenile populations. The updated system of designations of genetic groups introduced by WHO/OIE/FAO H5 Evolution Working Group in 2015 is used.
The SARS-CoV-2 betacoronavirus pandemic has claimed more than 6.5 million lives and, despite the development and use of COVID-19 vaccines, remains a major global public health problem. The development of specific drugs for the treatment of this disease remains a very urgent task. In the context of a repurposing strategy, we previously screened a library of nucleoside analogs showing different types of biological activity against the SARS-CoV-2 virus. The screening revealed compounds capable of inhibiting the reproduction of SARS-CoV-2 with EC50 values in the range of 20–50 µM. Here we present the design and synthesis of various analogs of the leader compounds, the evaluation of their cytotoxicity and antiviral activity against SARS-CoV-2 in cell cultures, as well as experimental data on RNA-dependent RNA polymerase inhibition. Several compounds have been shown to prevent the interaction between the SARS-CoV-2 RNA-dependent RNA polymerase and the RNA substrate, likely inhibiting virus replication. Three of the synthesized compounds have also been shown to inhibit influenza virus. The structures of these compounds can be used for further optimization in order to develop an antiviral drug.
Introduction. The new reassortant of the swine flu virus A(H1N1)pdm09, which emerged in 2009, overcame the species barrier and caused the 2009-2010 pandemic. One of the key points required for the influenza virus to overcome the species barrier and adapt it to humans is its specific binding to the receptors on the epithelium of the human respiratory tract.Targets and goals. Studying the dynamics of changes in receptor specificity (RS) of the HA1 subunit of the hemagglutinin of the influenza A(H1N1)pdm09 virus strains isolated during the period 2009-2016 on the territory of the Russian Federation, and an analysis of the possible impact of these changes on the incidence rates of the population of the Russian Federation of pandemic influenza in certain epidemic seasons. Material and Methods. Standard methods of collecting clinical materials, isolation of influenza viruses, their typing and genome sequencing were used. For the study of RS of influenza A virus (H1N1)pdm09, the method of solid phase sialosidenzyme analysis was used. Results. It is shown that the change in the parameter W3/6 , which characterizes the degree of a2-3 receptor specificity (a2-3-RS) of the influenza virus A(H1N1)pdm09 over a2-6-RS, coincides with the change in the incidence rates of the Russian Federation’s pandemic flu in separate epidemic seasons. There is a tendency to increase the affinity of the virus A(H1N1)pdm09 to α2-3 analogs of the sialyl-glycan receptors of the human respiratory tract epithelium - α2-3-sialoglycopolymers (α2-3-SGP), and falls to α2-6-SGP, with the virus showing the greatest affinity for sulfated sialoglycopolymers. Discussion. Screening for RS strains of influenza A (H1N1)pdm09 virus isolated on the territory of the Russian Federation in 2009-2016 revealed a decrease in the affinity of viruses for a2-6-sialosides, especially for 6’SL-SGP, which is probably due to the presence of amino acid substitutions in the 222 and 223 positions of RBS HA1 viruses. Previous studies have shown that the presence of such substitutions correlates with an increase in the virulence of the influenza A virus (H1N1)pdm09 [16, 23]. Probably, the pandemic virus has evolved towards the selection of more virulent pneumotropic variants. Conclusion. Monitoring of the receptor specificity of a pandemic influenza virus makes it possible to identify strains with altered RS to the epithelium of the human respiratory tract and an increased ability to transfer from person to person. Change in the period 2009-2016 the W3/6 parameter characterizing the degree of α2-3-RS excess of the influenza A(H1N1)pdm09 virus over α2-6-RS, coincides with the change in the incidence rates of the pandemic influenza population of the Russian Federation in certain epidemic seasons.
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