Comparative Analysis of Biological Properties of Influenza А (Н1N1) pdm09 Virus Strains isolated in the Pandemic of 2009 and the Post-Pandemic Period in the Asian Part of Russia

Comparative analysis of influenza A (H1N1) pdm09 virus strains isolated in Russian Asia in the pandemic of 2009 and the post-pandemic period of 2011 was carried out. It was shown that pandemic influenza А (H1N1) pdm09 virus strain isolated in the pandemic period is more virulent and able to cause more severe pathological processes in lung tissue of experimentally infected mice compared to the strain А (H1N1) pdm09 isolated in the post-pandemic period. It is probably associated with mutations in genes encoding surface proteins that occurred at the time of influenza A (H1N1) pdm09 virus circulation from 2009 to 2011 and that resulted in emergence of new genetic variants of virus with lower virulence.