Relevance. Influenza viruses, having an extremely high variability of the genome and significant environmental plasticity, continue to maintain a potential threat to the biological safety of mankind. The purpose Aims of the work is to analyze the features of the epidemic season of2017-2018. Materials and methods . The collection of data on the incidence and laboratory diagnosis of influenza and ARVI was carried out in the framework of the epidemiological surveillance of the circulation of influenza viruses in the Russian Federation. The observation period was from 40 weeks (october) 2017 to 25 weeks (june) 2018. The typing of the isolates was performed in the reaction of inhibition of hemagglutination activity (HI) according to the standard technique with diagnostic sera to reference and epidemic influenza viruses. Results and discussion . The article presents the features of the influenza virus circulation n for the period from october 2017 to may 2018 in some territories of Russia, collaborating with D. I. Ivanovsky Institute of Virology. The epidemic season had its own peculiarities: delayed and long-term activity of three influenza viruses, the share participation of which was almost equal, with some dominance of the influenza A(H1N1)pdm09 virus by the end of the season. Morbidity rates for the total population were comparable with the last epidemic season, meantime the morbidity among schoolchildren was higher. The number of hospitalizations and lethal outcomes was lower and mostly was found in patients of 65 years and older. In patients with severe acute respiratory infection (SARI) influenza A(H1N1)pdm09 was detected more frequently (58%). The influenza A(H1N1)pdm09 and A(H3N2) viruses were antigenically similar to strains included in influenza vaccines, at the same time, 96% of the isolated strains of influenza B virus belonged to a different evolutionary line. Epidemic strains were sensitive to neuraminidase inhibitors, except for 5 strains of influenza A(H1N1)pdm09 virus, isolated from pregnant women. Conclusions. The activity of non- influenza ARI viruses was similar to preliminary epidemic seasons. Recommendations on the influenza vaccines composition for the Northern hemisphere for 2019-2020 season are presented as well.

Благодаря новым методам диагностики инфекционных заболеваний накопилось много данных о новых пневмотропных вирусах - метапневмовирусе и бокавирусе, вызывающих инфекции, часто с осложнениями в виде тяжелых бронхиолитов, альвеолитов и пневмоний, особенно у детей с ослабленной иммунной системой. Нередко при бокавирусной инфекции имеет место сочетанное поражение дыхательных путей и ЖКТ в форме гастроэнтерита. В настоящее время не существует разработанного этиотропного лечения метапневмо- и боковирусной инфекций. Развитию острых инфекционно-воспалительных заболеваний дыхательных путей и их осложнений, таких как пневмония, гайморит, отит и др. способствуют различные нарушения в иммунной системе, одним из важнейших компонентов которой является система интерферонов. Индуктор интерферонов Кагоцел хорошо зарекомендовал себя в ряде экспериментальных и клинических исследований: у детей, получавших терапию Кагоцелом, независимо от этиологии выделенных вирусов, достоверно быстрее купировались лихорадка и признаки интоксикации, сокращались длительность катарального и воспалительного синдромов со стороны верхних и нижних дыхательных путей.

This work describes the specific features of the influenza virus circulating in the period from October 2015 to March 2016 in 10 cities of Russia, the basic laboratories of CEEI at the D.I. Ivanovsky Institute of Virology "Federal Research Centre of Epidemilogy and Microbiology named after the honorary academician N.F. Gamaleya" of the Ministry of Health of the Russian Federation. The increase in the morbidity caused by influenza viruses was detected in January-February 2016. The duration of the morbidity peak was 4-5 weeks. The most vulnerable group included children at the age from 3 to 6; a high rate of hospitalization was also detected among people at the age of 15-64 (65%). In clinic symptoms there were middle and severe forms with high frequency of hospitalization as compared with the season of 2009-2010, but much higher in comparison with the season of 2014-2015. Some of the hospitalized patients had virus pneumonias, half of which were bilateral. Among these patients, 10% were children; 30%, adults. The mortality in the intensive care unit of the hospital was 46%. Almost all lethal cases were among unvaccinated patients in the case of late hospitalization and without early antiviral therapy. The predominance of the influenza A(H1N1)09pdm virus both in the Russian Federation and the major part of the countries in the Northern hemisphere was noted. The results of the study of the antigenic properties of influenza strains of A(H1N1)pdm09 virus did not reveal any differences with respect to the vaccine virus. The sequencing data showed the amino acid substitutions in hemagglutinin (receptor binding and Sa sites) and in genes encoding internal proteins (PA, NP, M1, NS1). Strains were sensitive to oseltamivir and zanamivir and maintained resistance to rimantadine. The participation of non-influenza ARI viruses was comparable to that in preliminary epidemic seasons.

The aim of this study was to monitor in-hospital influenza virus infection during 2015 – 2016 epidemic flu season. Methods. Influenza virus was searched in patients hospitalized to a clinical infectious diseases hospital with acute respiratory viral infection during 2015 – 2016 influenza seasonal growth period using real-time RT-PCR method. Influenza virus was isolated from nasal swabs and autopsy material using canine kidney cell line. Other laboratory methods used included complete blood count, blood chemistry, blood gas analysis, urinalysis, and chest X-ray examination. Results. We examined 1,491 patients (375 adults, 546 children, 570 pregnant women with early gestational age). The proportion of hospitalized patients with confirmed A / H1N1pdm09 influenza in January – February, 2016, was 91.3%. A / H3N2 influenza virus was diagnosed in 5.7%, influenza B virus was isolated in 1.2% of patients. Totally, influenza virus was detected in 35.2% of samples, of which 30.1% of samples were obtained from adults, 33.7% of samples were obtained from children, and 39.8% of samples were obtained from pregnant women. The prevalent patient’s age was 15 to 60 years (76.1%) in adults and 3 to 6 years in children. Moderate course of influenza with a high rate of hospital admission was seen more often and was similar to that of 2009 – 2010 epidemic season. Proportion of patients with flu complicated by pneumonia was higher than that in 2014 – 2015 epidemic season. Bilateral lung injury was diagnosed in 48.4% of patients. High mortality in ICU (46.4%) was due to delayed start of antiviral treatment and late admission to a hospital. Conclusion. In 2015 – 2016 epidemic flu season, higher morbidity, complications and poor outcomes were related to predominant infection of A – H1N1pdm09 influenza virus. Risk factors of complications and death were delayed care seeking, lack of modern antiviral medications and comorbidity.

The results of study of the specific features of influenza virus circulation in 2013-2014 in 10 cities of Russia were presented. The results were obtained in basic laboratories of the Center for Ecology and Epidemiology of Influenza, D.I. Ivanovsky Institute of Virology, FSBI «N.F. Gamaleya FRCE M» Ministry of Health of the Russian Federation. The increasing rate of the ARD morbidity was detected during week 9 with further decrease in the morbidity rate till threshold levels reached during week 13. Children 0-2 years old and 3-6 years old were the most involved age group, while the highest rate of hospitalization was found in the age group of 15-64 years old (66%). The influenza A(H1N1)pdm09 and A(H3N2) viruses were the cause of the epidemic, but their activity differed over regions of Russia. The results of study of the antigenic and genetic properties of influenza strains showed for the most of them a close relation to the vaccine strains. Certain heterogeneity of circulating strains and their drift variants was found as well. All the tested strains were sensitive to the oseltamivir and zanamivir, while preserving resistance to the rimantadine. The ratio of the AR D viruses was comparable with the last epidemic seasons.

The peculiarities of the influenza viruses circulation in 2012-2013 are discussed. The results were obtained in 10 cities of Russia, where basic laboratories of the Influenza Ecology and Epidemics Center of on the basis of Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, are situated. The increasing rate of the ARD morbidity caused by influenza viruses was observed in January-March 2013. The highest indices of the morbidity were detected during 6-7 weeks with the following decreasing rate till threshold levels to week 14. The influenza A (H1N1) pdm09, A (H3N2), and B viruses were the cause of the epidemic, but their activity differed over areas of Russia. The results of study of the antigenic and genetic properties of the influenza strains demonstrated closed relatives with respect to vaccine strains. In addition, some heterogeneity of the circulating strains and their drift variants were found as well. All tested strains were sensitive to oseltamivir (excluding one A (H1N1) pdm09 strain), zanamivir, arbidol, and remained resistant to rimantadine. The ratio of the ARD viruses was comparable with the last epidemic seasons.

The results of the genetic studies of influenza viruses make it possible to understand their evolution and recommendations for vaccine strains content. In this work, the data of complete sequence of the На, NA, and M2-protein for 34 strains of influenza A(H3N2) virus circulating in russia during 2007-2012 are presented. the influenza strains were isolated in ivanovsky institute of Virology, Moscow, and some collaborating russian centers. the results of the phylogenetic analysis showed the differences among strains, which were observed during the analyzed period; the evolution had direction from A/Brisbane/10/2007 to A/Perth/16/2009 and А/ Victoria/208/2009. hemagglutinin of the influenza A(H3N2) virus strains had differences between strains of last two seasons and strains circulating before, in the antigenic sites A, B, D, and, to a lesser extent, c, and E. in the neuraminidase gene the mutations responsible for the resistance to oseltamivir (E119V, R292K, N294s) and zanamivir (Q136K) were not found. All isolates carry the s31N mutation in the M2 gene responsible for resistance to amantadine.

The results of analysis of the peculiarities of the epidemic 2011-2012 development in the areas of 10 cities of Russia obtained by basic laboratories of IEES on the base of D.I. Ivanovsky Research Institute of Virology, Ministry of Public Health and Social Development of Russia, are presented. The increasing ARD morbidity caused by the influenza viruses was detected rather late--in February-March 2012. The highest indices of the morbidity were detected during weeks 10-13 followed by decreasing to threshold levels by week 27. Children 0-2 and 3-6 years old were involved the most, meantime the high rate of hospitalization was found for 15-64 years old aged group (25%). Influenza A(H3N2) and B viruses were the cause of the epidemic. The results of studies of the antigenic and genetic properties of the influenza strains showed most of them to be close relatives to the vaccine strains. Some heterogeneity of circulating strains and their drift variants were found as well. All tested strains were sensitive to arbidol, oseltamivir and zanamivir, and saved resistance to rimantadine. The ratio of ARD viruses was comparable with the last epidemic seasons.

The paper gives the results of monitoring the circulation of influenza viruses in the 2010-2011 season, that covers the second year of circulation of pandemic A(H1N1)v virus strains, and their interaction with seasonal A (H3N2) and B strains. Unlike the previous season, the beginning of an increase in morbidity was recorded in January 2011; its peak in the most of contiguous areas was noted at 5-7 weeks of 2011, with its further decline to threshold levels at week 11 of 2011. Preschool and school children were most involved in the epidemic process. Three influenza virus strains (A(H1N1)v, A(H3N2), and B) were found to circulate. Differences were found in the level of participation of the isolated strains in individual areas of the Russian Federation. Detailed typing of the isolated strains determined the compliance of the vast majority of them with vaccine viruses. The pandemic influenza A(H1N1)v virus strains retained their susceptibility to oseltamivir and were resistant to rimantadine. The participation of non-influenza acute respiratory viral infection pathogens was estimated as follows: 11.9% for parainfluenza viruses, 5.9% for adenoviruses, and 3.5% for PC viruses, and 0.7% for pneumonia Mycoplasma, which was comparable with the previous epidemic seasons.