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Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models.

ABSTRACT: Low-pathogenicity avian influenza A(H9N2) viruses, enzootic in poultry populations in Asia, are associated with fewer confirmed human infections but higher rates of seropositivity compared to A(H5) or A(H7) subtype viruses. Cocirculation of A(H5) and A(H7) viruses leads to the generation of reassortant viruses bearing A(H9N2) internal genes with markers of mammalian adaptation, warranting continued surveillance in both avian and human populations. Here, we describe active surveillance efforts in live poultry markets in Vietnam in 2018 and compare representative viruses to G1 and Y280 lineage viruses that have infected humans. Receptor binding properties, pH thresholds for HA activation, in vitro replication in human respiratory tract cells, and in vivo mammalian pathogenicity and transmissibility were investigated. While A(H9N2) viruses from both poultry and humans exhibited features associated with mammalian adaptation, one human isolate from 2018, A/Anhui-Lujiang/39/2018, exhibited increased capacity for replication and transmission, demonstrating the pandemic potential of A(H9N2) viruses.IMPORTANCE A(H9N2) influenza viruses are widespread in poultry in many parts of the world and for over 20 years have sporadically jumped species barriers to cause human infection. As these viruses continue to diversify genetically and antigenically, it is critical to closely monitor viruses responsible for human infections, to ascertain if A(H9N2) viruses are acquiring properties that make them better suited to infect and spread among humans. In this study, we describe an active poultry surveillance system established in Vietnam to identify the scope of influenza viruses present in live bird markets and the threat they pose to human health. Assessment of a recent A(H9N2) virus isolated from an individual in China in 2018 is also reported, and it was found to exhibit properties of adaptation to humans and, importantly, it shows similarities to strains isolated from the live bird markets of Vietnam.

SUBMITTER: Belser JA

PROVIDER: S-EPMC7431790 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models.

Belser Jessica A JA Sun Xiangjie X Brock Nicole N Pappas Claudia C Pulit-Penaloza Joanna A JA Zeng Hui H Jang Yunho Y Jones Joyce J Carney Paul J PJ Chang Jessie J Long Nguyen Van NV Diep Nguyen Thi NT Thor Sharmi S Di Han H Yang Genyan G Cook Peter W PW Creager Hannah M HM Wang Dayan D McFarland Jeffrey J Dong Pham Van PV Wentworth David E DE Tumpey Terrence M TM Barnes John R JR Stevens James J Davis C Todd CT Maines Taronna R TR

Journal of virology 20200817 17

Low-pathogenicity avian influenza A(H9N2) viruses, enzootic in poultry populations in Asia, are associated with fewer confirmed human infections but higher rates of seropositivity compared to A(H5) or A(H7) subtype viruses. Cocirculation of A(H5) and A(H7) viruses leads to the generation of reassortant viruses bearing A(H9N2) internal genes with markers of mammalian adaptation, warranting continued surveillance in both avian and human populations. Here, we describe active surveillance efforts in ...[more]

PMID: 32611751

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Dataset Information

Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models.

Publications

Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models.

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