The infection of turkeys and chickens by reassortants derived from pandemic H1N1 2009 and avian H9N2 influenza viruses

Abstract

Outbreaks of pandemic H1N1 2009 (pH1N1) in turkeys have been reported in several countries. Co-infection of pH1N1 and avian H9N2 influenza viruses in turkeys provide the opportunity for their reassortment, and novel reassortant viruses might further be transmitted to other avian species. However, virulence and transmission of those reassortant viruses in poultry remain unclear. In the present study, we generated 16 single-gene reassortant influenza viruses including eight reassortants on the pH1N1 background by individual replacement with a corresponding gene segment from H9N2 and eight reassortants on the H9N2 background replaced individually with corresponding gene from pH1N1, and characterized reassortants viruses in turkeys and chickens. We found that the pH1N1 virus dramatically increased its infectivity and transmissibility in turkeys and chickens after introducing any gene (except for PB2) from H9N2 virus, and H9N2 virus acquired single gene (except for HA) of pH1N1 almost did not influence its replication and transmission in turkeys and chickens. Additionally, 13 reassortant viruses transmitted from turkeys to chickens. Our results indicate that turkeys and chickens are susceptible to pH1N1-H9N2 reassortant viruses, and mixing breeding of different avian species would facilitate the transmission of these reassortant viruses.

Non-basic amino acids in the hemagglutinin proteolytic cleavage site of a European H9N2 avian influenza virus modulate virulence in turkeys

“…Poor replication of two Dutch wild-bird-origin H9N2 viruses in chickens as indicated by lack of clinical signs, low virus titers in swabs and respiratory organs and low seroconversion has been reported 41 . Conversely, efficient replication and transmission of a chicken-adapted virus Ck/Hebei/LC/2008 H9N2 in chickens and turkeys have been reported, although cloacal excretion was not seen in turkeys 51 .…”

NS Segment of a 1918 Influenza A Virus-Descendent Enhances Replication of H1N1pdm09 and Virus-Induced Cellular Immune Response in Mammalian and Avian Systems

“…In our present study, susceptibility of chickens to the recombinant isolate Gi-wt was not increased by NS-reassortment of PR8. However, recent in vivo experiments showed that single replacement of specific segments (including the NS segment) of a pandemic H1N1 strain (A/Beijing/16/2009) by viral segments of A/chicken/Hebei/LC/2008 (H9N2) enabled the reassortant viruses to transmit/replicate in chickens, which are otherwise refractory to infection with the wild-type virus ( Sun et al, 2015 ). Taken together, these results implicate that the ability of H1N1pdm09 to cross the species barrier to chickens after NS-reassortment is based on the specific genetic backbone of the respective H1N1pdm09 strain, as well as the particular NS segment/-donor strain.…”

Human to animal transmission of influenza A(H1N1)pdm09 in a turkey breeder flock in Norway

“…Although turkeys are not normally regarded as potential ‘mixing vessels’ for influenza viruses, they are susceptible to a wide variety of IAVs, including those from wild birds, swine and humans, providing the opportunity for influenza virus reassortants [22,23]. In that context, this paper adds to the discussions regarding the usefulness of vaccination in poultry farm workers.…”