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J Virol. 2015 Apr 1. pii: JVI.00459-15. [Epub ahead of print]
Continual Re-Introduction of Human Pandemic H1N1 Influenza A Viruses into US Swine, 2009-2014.
Nelson MI1, Stratton J2, Killian ML3, Janas-Martindale A3, Vincent AL2.
Author information
Abstract
The diversity of influenza A viruses in swine (swIAVs) presents an important pandemic threat. Knowledge of the human-swine interface is particularly important for understanding how viruses with pandemic potential evolve in swine hosts. Through phylogenetic analysis of contemporary swIAVs in the United States, we demonstrate that human-to-swine transmission of pandemic H1N1 viruses (pH1N1) has occurred continuously in the years following the 2009 H1N1 pandemic and has been an important contributor to the genetic diversity of US swIAVs. Although pandemic H1 and N1 segments were largely removed from the US swine population by 2013 via reassortment with other swIAVs, these antigens re-emerged following multiple human-to-swine transmission events during the 2013-2014 seasonal epidemic. These findings indicate that the six internal gene segments from pH1N1 viruses are likely to be sustained long-term in the US swine population, with periodic re-emergence of pandemic HA and NA segments in association with seasonal pH1N1 epidemics in humans. Vaccinating US swine workers may reduce infection of both humans and swine, and in turn limit the role of humans as sources of influenza virus diversity in pigs.
IMPORTANCE:
Swine are important hosts in the evolution of influenza A viruses with pandemic potential. Here we analyze influenza virus sequence data generated by the US Department of Agriculture's national surveillance system to identify the central role of humans in the re-emergence of pandemic H1N1 influenza viruses (pH1N1) in US swine herds in 2014. These findings emphasize the important role of humans as continuous sources of influenza virus diversity in swine, and indicate that influenza viruses with pandemic HA and NA segments are likely to continue to re-emerge US swine in association with seasonal pH1N1 epidemics in humans.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 25833052 [PubMed - as supplied by publisher]
Continual Re-Introduction of Human Pandemic H1N1 Influenza A Viruses into US Swine, 2009-2014.
Nelson MI1, Stratton J2, Killian ML3, Janas-Martindale A3, Vincent AL2.
Author information
Abstract
The diversity of influenza A viruses in swine (swIAVs) presents an important pandemic threat. Knowledge of the human-swine interface is particularly important for understanding how viruses with pandemic potential evolve in swine hosts. Through phylogenetic analysis of contemporary swIAVs in the United States, we demonstrate that human-to-swine transmission of pandemic H1N1 viruses (pH1N1) has occurred continuously in the years following the 2009 H1N1 pandemic and has been an important contributor to the genetic diversity of US swIAVs. Although pandemic H1 and N1 segments were largely removed from the US swine population by 2013 via reassortment with other swIAVs, these antigens re-emerged following multiple human-to-swine transmission events during the 2013-2014 seasonal epidemic. These findings indicate that the six internal gene segments from pH1N1 viruses are likely to be sustained long-term in the US swine population, with periodic re-emergence of pandemic HA and NA segments in association with seasonal pH1N1 epidemics in humans. Vaccinating US swine workers may reduce infection of both humans and swine, and in turn limit the role of humans as sources of influenza virus diversity in pigs.
IMPORTANCE:
Swine are important hosts in the evolution of influenza A viruses with pandemic potential. Here we analyze influenza virus sequence data generated by the US Department of Agriculture's national surveillance system to identify the central role of humans in the re-emergence of pandemic H1N1 influenza viruses (pH1N1) in US swine herds in 2014. These findings emphasize the important role of humans as continuous sources of influenza virus diversity in swine, and indicate that influenza viruses with pandemic HA and NA segments are likely to continue to re-emerge US swine in association with seasonal pH1N1 epidemics in humans.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 25833052 [PubMed - as supplied by publisher]