title: Pathogenicity and transmissibility of reassortant H9 influenza viruses with genes from pandemic H1N1 virus.
abstract: Both H9N2 avian influenza and 2009 pandemic H1N1 viruses (pH1N1) are able to infect humans and swine, which has raised concerns that novel reassortant H9 viruses with pH1N1 genes might be generated in these hosts by reassortment. Although previous studies have demonstrated that reassortant H9 viruses with pH1N1 genes show increased virulence in mice and transmissibility in ferrets, the virulence and transmissibility of reassortant H9 viruses in natural hosts such as chickens and swine remain unknown. This study generated two reassortant H9 viruses (H9N2/CA09 and H9N1/CA09) in the background of the pH1N1 A/California/04/2009 (CA09) virus by replacing either both the haemagglutinin (HA) and neuraminidase (NA) genes or only the HA gene with the respective genes from the A/quail/Hong Kong/G1/1997 (H9N2) virus and evaluated their replication, pathogenicity and transmission in chickens and pigs compared with the parental viruses. Chickens that were infected with the parental H9N2 and reassortant H9 viruses seroconverted. The parental H9N2 and reassortant H9N2/CA09 viruses were transmitted to sentinel chickens, but H9N1/CA09 virus was not. The parental H9N2 replicated poorly and was not transmitted in pigs, whereas both H9N2/CA09 and H9N1/CA09 viruses replicated and were transmitted efficiently in pigs, similar to the pH1N1 virus. These results demonstrated that reassortant H9 viruses with pH1N1 genes show enhanced replication and transmissibility in pigs compared with the parental H9N2 virus, indicating that they may pose a threat for humans if such reassortants arise in swine.
authors.affiliation: Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, PR China.|Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Chuanling
authors.initials: C
authors.lastname: Qiao
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Qinfang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Bawa
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Huigang
authors.initials: H
authors.lastname: Shen
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Wenbao
authors.initials: W
authors.lastname: Qi
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Centre of Influenza Research, School of Public Health, The University of Hong Kong, Hong Kong SAR.
authors.forename: Chris Ka Pun
authors.initials: CKP
authors.lastname: Mok
authors.affiliation: Global Health and Emerging Pathogens Institute, Mount Sinai School of Medicine, NY 10029, USA.|Department of Medicine, Division of Infectious Diseases, Mount Sinai School of Medicine, NY 10029, USA.|Department of Microbiology, Mount Sinai School of Medicine, NY 10029, USA.
authors.forename: Adolfo
authors.initials: A
authors.lastname: García-Sastre
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Jürgen A
authors.initials: JA
authors.lastname: Richt
authors.affiliation: Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Ma
mesh_terms: D000818:Animals; D002460:Cell Line; D002645:Chickens; D004285:Dogs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics*; D053127:Influenza A Virus, H9N2 Subtype / Q000235:genetics*; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D058873:Pandemics; D011201:Poultry Diseases / Q000635:transmission / Q000821:virology; D011897:Random Allocation; D016865:Reassortant Viruses / Q000235:genetics*; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D013553:Swine Diseases / Q000635:transmission / Q000821:virology