Vol 64, No 2 (2019)

Human adenoviruses cause different organ infections of varying severity, from asymptomatic to severe cases with lethal outcome, that are registered everywhere. Detailed and focused study of factors predisposing to a severe course of infection is required. The literature contains information indicating the association of severe adenoviral respiratory diseases with certain types of adenovirus, primarily type 7. This review highlights the possible causes of increased pathogenicity of some types of adenovirus and their association with severe forms of infection. Pathogenicity factors include the ability of adenovirus to bind the specific cellular receptors, the formation of subviral particles, the interaction with blood proteins, in particular the coagulation factor X, as well as the features of the early genes E1A, E1B, E3, E4. In addition, the severity of the disease may be affected by the presence or absence of pre-existing antibodies specific to certain types of adenoviruses. Chronic diseases or immunosuppression also increase the risk of severe adenovirus infection. The information presented in this review may elucidate the pathogenesis of adenovirus infection, and help to develop new features for prevention and treatment.

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.

Introduction. Molecular-genetic monitoring of human immunodeficiency virus (HIV) drug-resistant strains circulation as well as analysis of territorial peculiarities of different genetic variants prevalence of the virus is a crucial part of epidemiological surveillance over HIV-infection spread. Objective of the research - to analyze the prevalence of HIV-1 genetic variants among HIV-positive people living in different constituent entities of the Far Eastern Federal District. Material and methods. Molecular-genetic analysis of the Pol-gene that is coding protease and a part of reverse transcriptase of HIV-1 was performed for a total number of 206 blood plasma samples. The biological material was collected from HIV-positive people living in Sakhalin, Magadan and Amur regions, Jewish Autonomous District, Khabarovsk region, Republic of Sakha (Yakutia) and Chukotka Autonomous Region (constituent entities of the Russian Federation in the Russian Far East). Results. The research demonstrated that HIV-1 sub-subtype A6 continues to be dominant and comprises 72.1±3.1% of all isolated subtypes in the regions of the Russian Far East. HIV-1 subtype B was identified in 14 cases (6.8±1.8%) and subtype C in 4 cases (1.9±1.0%). Spectrum of HIV-1 recombinant forms was determined for some regions. We identified five types of HIV-1 circulating recombinant forms (CRF): CRF03_AB - 2 (0.9±0.7%), CRF02_AG - 8 (3.9±1.3%), CRF63_02A1 - 27 (13.1±2.4%), CRF11_cpx - 1 (0.5±0.5%), CRF01_AE - 3 (1.5±0.8%). High heterogeneity of the virus was registered in the Jewish Autonomous District. Discussion. The conducted research revealed genetic differences in the landscape of HIV-1 subtypes circulation as well as differences in HIV-1 recombinant forms distribution frequency in the Russian Far East. Current findings are due to expansion of migration flows that promote cross-border importation and further spread of different HIV-1 genetic variants among population of the Far Eastern Federal District. Conclusion. The conducted research revealed that the molecular-genetic monitoring of HIV-1 genovariants should involve not only regions with high HIV-abundance but also with low HIV-prevalence and incidence.