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Virology. Rapid adaptation of avian H7N9 virus in pigs

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  • Virology. Rapid adaptation of avian H7N9 virus in pigs

    [Source: Virology, full page: (LINK). Abstract, edited.]

    Virology, Volumes 452?453, March 2014, Pages 231?236 / Brief Communication

    Rapid adaptation of avian H7N9 virus in pigs

    Lili Xu<SUP>a</SUP>, Linlin Bao<SUP>a</SUP>, Wei Deng<SUP>a</SUP>, Hua Zhu<SUP>a</SUP>, Fengdi Li<SUP>a</SUP>, Ting Chen<SUP>a</SUP>, Qi Lv<SUP>a</SUP>, Jing Yuan<SUP>a</SUP>, Yanfeng Xu<SUP>a</SUP>, Yanhong Li<SUP>a</SUP>, Yanfeng Yao<SUP>a</SUP>, Songzhi Gu<SUP>a</SUP>, Pin Yu<SUP>a</SUP>, Honglin Chen<SUP>b</SUP>, Chuan Qin<SUP>a</SUP>
    <SUP>a</SUP> Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China; <SUP>b</SUP> State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology and the Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong SAR, China

    Received 7 November 2013, Revised 13 December 2013, Accepted 20 January 2014, Available online 14 February 2014

    • Avian-origin H7N9 virus replicate to high titers after one passage in pigs.
    • Human isolated H7N9 virus replicate poorly after three passages in pigs.
    • Nine mutations enhance the binding affinity for human-type receptors of the avian isolated H7N9.
    • Human H7N9 virus develops enhanced affinity for avian-type receptors after 3 passages in pigs.


    How the H7N9 avian influenza virus gained the distinct ability to infect humans is unclear. Pigs are an important host in influenza virus ecology because they are susceptible to infection with both avian and human influenza viruses and are often involved in interspecies transmission. Here, we passaged one avian isolate and one human isolate in pigs to examine the mammalian host adaptation of the H7N9 virus. The avian virus replicated to a high titer after one passage, whereas the human isolate replicated poorly after three passages in pig lungs. Sequence analysis found nine substitutions in the HA, NA, M and NS segments of the avian isolate, which enhanced the binding affinity for human-type receptors. These results indicate that avian H7N9 influenza viruses can be easily adapted to pigs and that pigs may act as an important intermediate host for the reassortment and transmission of such novel viruses.


    H7N9 influenza virus; Pig; Adaptation; Mutation; Receptor binding

    Corresponding author. Tel.: +86 10 677 619 42, fax: +86 10 677 619 43.

    Copyright ? 2014 Elsevier Inc. All rights reserved.