The molecular-genetic and phylogenetic analysis of the hemaglutinin gene from influenza viruses

Aim. To perform a phylogenetic and molecular-genetic analysis of the HA genes of influenza viruses that circulated in Ukraine during the 2016–2017 epidemic season, and to compare them with those that circulated in the world. Methods. Samples (nasopharyngeal swabs from patients) were analyzed using the real-time polymerase chain reaction (RT-PCR). Phylogenetic trees were constructed using MEGA 7 software. 3D structures were constructed in Chimera 1.11.2rc software. Results. Ukrainian isolates from the 2016–2017 season have substitutions in the antigenic sites which were not detected earlier; they and can influence the antigenic properties of viruses. Otherwise the A(H3N2) and B/Victoria viruses retained the similarity to the vaccine strains. For the A(H1N1)pdm09, a higher similarity to the vaccine strain recommended for the 2017–2018 epidemic season was observed. Conclusions. In the 2016–2017 epidemic season, all influenza viruses –A(H3N2), A(H1N1)pdm09 and B/Victoria acquired a number of unique amino-acid substitutions in the HA gene. The results of this study reaffirm the continuous genetic variability of circulating seasonal influenza viruses and the need for continued systematic antigenic and molecular surveillance.