Cell Reports (Sep 2015)

Testing the Effect of Internal Genes Derived from a Wild-Bird-Origin H9N2 Influenza A Virus on the Pathogenicity of an A/H7N9 Virus

  • Wen Su,
  • Chengmin Wang,
  • Jing Luo,
  • Yuliang Zhao,
  • Yan Wu,
  • Lin Chen,
  • Na Zhao,
  • Meng Li,
  • Chao Xing,
  • Huimin Liu,
  • Hong Zhang,
  • Yung-fu Chang,
  • Tianxian Li,
  • Hua Ding,
  • Xiufeng Wan,
  • Hongxuan He

DOI
https://doi.org/10.1016/j.celrep.2015.08.029
Journal volume & issue
Vol. 12, no. 11
pp. 1831 – 1841

Abstract

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Since 2013, avian influenza A(H7N9) viruses have diversified into multiple lineages by dynamically reassorting with other viruses, especially H9N2, in Chinese poultry. Despite concerns about the pandemic threat posed by H7N9 viruses, little is known about the biological properties of H7N9 viruses that may recruit internal genes from genetically distinct H9N2 viruses circulating among wild birds. Here, we generated 63 H7N9 reassortants derived from an avian H7N9 and a wild-bird-origin H9N2 virus. Compared with the wild-type parent, 25/63 reassortants had increased pathogenicity in mice. A reassortant containing PB1 of the H9N2 virus was highly lethal to mice and chickens but was not transmissible to guinea pigs by airborne routes; however, three substitutions associated with adaptation to mammals conferred airborne transmission to the virus. The emergence of the H7N9-pandemic reassortant virus highlights that continuous monitoring of H7N9 viruses is needed, especially at the domestic poultry/wild bird interface.