GENETIC CHARACTERISTICS OF INFLUENZA A/H3N2 AND В VIRUSES THAT HAD CIRCULATED IN RUSSIA IN 2013 - 2015

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Aim. Establish genetic characteristics, carry out phylogenetic analysis and determination of molecular markers of resistance to etiotropic preparations against influenza A/H3N2 and В viruses that had circulated in Russia in 2013 - 2015. Materials and methods. 80 biological samples containing influenza A/H3N2 virus RNA and 31 samples containing influenza В virus RNA were studied. Sequencing of PCR fragments was carried out in ABI-3100 PRIZMTM GeneticAnalyzer (AppliedBiosystems, USA) and using MiSeq (Illumina, USA). Data treatment and analysis was carried out using CLC v.3.6.5., DNASTAR and BioNumerics v.6.5. programs. Results. In 2013 - 2014 A/Texas/50/2012-like clade 3C.3 influenza A/H3N2 viruses dominated, 10% belonged to subclade 3C.2a and 10% - to ЗС.ЗЬ. Most of the viruses (81%) of 2014 - 2015 were of 3C.2a clade, the portion of viruses belonging to ЗС.ЗЬ and ЗС.За was 9 and 10%. Yamagata-like viruses predominated among the studied influenza В viruses, only 1 virus of 2014 - 2015 belonged to Victoria lineage, 1 reassortant of Yamagata and Victoria lineages was detected. Rimantadine-resistance mutation S31N (М2 protein) was detected in all the influenza A/H3N2 viruses. Mutations determining resistance to oseltamivir (NA gene) were not detected in influenza A/H3N2 and В viruses. Conclusion. Increase of influenza morbidity in 2014 - 2015 was determined by the emergence of influenza A/H3N2 and В viruses, antigenically distinct from those that had circulated previously and those included into the vaccine, thus resulting in the WHO decision to change А/ H3N2 and В components of the 2015 - 2016 vaccine. Simultaneous circulation of 2 lineages of influenza В virus and emergence of their reassortants gives evidence on the necessity of use of quadrivalent vaccines, containing both lineages.

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