The NS Segment of H1N1pdm09 Enhances H5N1 Pathogenicity in a Mouse Model of Influenza Virus Infections

Viruses. 2018 Sep 17;10(9):504. doi: 10.3390/v10090504.


In 2009, the co-circulation of H5N1 and H1N1pdm09 raised concerns that a reassortment event may lead to highly pathogenic influenza strains. H1N1pdm09 and H5N1 are able to infect the same target cells of the lower respiratory tract. To investigate the capacity of the emergence of reassortant viruses, we characterized viruses obtained from the co-infection of cells with H5N1 (A/Turkey/13/2006) and H1N1pdm09 (A/Lyon/969/2009 H1N1). In our analysis, all the screened reassortants possessed the PB2, HA, and NP segments from H5N1 and acquired one or two of the H1N1pdm09 segments. Moreover, the in vivo infections showed that the acquisition of the NS segment from H1N1pdm09 increased the virulence of H5N1 in mice. We conclude, therefore, that reassortment can occur between these two viruses, even if this process has never been detected in nature.

Keywords: H1N1pdm; H5N1; influenza; influenza A; mouse model; pathogenicity; reassortment; virus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Coinfection
  • Disease Models, Animal
  • Genome, Viral
  • Influenza A Virus, H1N1 Subtype / physiology*
  • Influenza A Virus, H5N1 Subtype / physiology*
  • Mice
  • Morbidity
  • Orthomyxoviridae Infections / virology*
  • RNA, Viral
  • Reassortant Viruses
  • Viral Load
  • Viral Nonstructural Proteins / genetics*
  • Viral Nonstructural Proteins / metabolism*
  • Virulence
  • Virulence Factors
  • Virus Replication


  • NS protein, influenza virus
  • RNA, Viral
  • Viral Nonstructural Proteins
  • Virulence Factors