1. Evolution of the H9N2 influenza genotype that facilitated the genesis of the novel H7N9 virus
- Author
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Robert A. Carter, Min Wang, Gang Wu, Jinliang Wang, Jinhua Liu, Gordon Lemmon, Yanbo Yin, Chu Wen, Susu Duan, Guanlong Xu, Baoli Zhu, Hui Zhang, Wei Yandi, Honglei Sun, Dongdong Wang, Robert G. Webster, Shuoguo Wang, Jinnan Bao, Guozhong Zhang, Qian Wang, Jixun Zhao, Yuannian Jiao, Meng Sun, Juan Pu, Yipeng Sun, and Qian Du
- Subjects
China ,Genes, Viral ,Genotype ,animal diseases ,viruses ,Hemagglutinin Glycoproteins, Influenza Virus ,Biology ,medicine.disease_cause ,Influenza A Virus, H7N9 Subtype ,H5N1 genetic structure ,Virus ,Evolution, Molecular ,Pandemic ,Reassortant Viruses ,Influenza, Human ,medicine ,Antigenic variation ,Influenza A Virus, H9N2 Subtype ,Animals ,Humans ,Antigens, Viral ,Pandemics ,Phylogeny ,Retrospective Studies ,Multidisciplinary ,Genetic Drift ,Outbreak ,virus diseases ,Biological Sciences ,Virology ,Antigenic Variation ,Influenza A virus subtype H5N1 ,Influenza in Birds ,Chickens - Abstract
The emergence of human infection with a novel H7N9 influenza virus in China raises a pandemic concern. Chicken H9N2 viruses provided all six of the novel reassortant’s internal genes. However, it is not fully understood how the prevalence and evolution of these H9N2 chicken viruses facilitated the genesis of the novel H7N9 viruses. Here we show that over more than 10 y of cocirculation of multiple H9N2 genotypes, a genotype (G57) emerged that had changed antigenicity and improved adaptability in chickens. It became predominant in vaccinated farm chickens in China, caused widespread outbreaks in 2010–2013 before the H7N9 viruses emerged in humans, and finally provided all of their internal genes to the novel H7N9 viruses. The prevalence and variation of H9N2 influenza virus in farmed poultry could provide an important early warning of the emergence of novel reassortants with pandemic potential.
- Published
- 2014