Molecular evolutionary and antigenic characteristics of newly isolated H9N2 avian influenza viruses in Guangdong province, China
Four new H9N2 avian influenza viruses (AIVs) were isolated from domestic birds in Guangdong between December 2015 and April 2016. Nucleotide sequence comparisons indicated that most of the internal genes of these four strains were highly similar to those of human H7N9 viruses. Amino acid substitutions and deletions found in the HA and NA proteins indicated that all four of these new isolates may have an enhanced ability to infect humans and other mammals. A cross-hemagglutinin-inhibition assay, conducted with two vaccine strains that are broadly used in China, suggested that antisera against vaccine candidates could not provide complete inhibition of the new isolates.
This study was supported by the Young Scientists Fund of National Natural Science Foundation of China (NSFC) (31800141), Natural Science Foundation of Guangdong Province, China (2017A030310573), High-Level Talent Start-Up Research Project of the Foshan University (Gg040967), National Natural Science Foundation of China (31400150).
Compliance with ethical standards
Ethics approval and consent to participate
The swab sampling and experiments were approved by the Institutional Animal Care and Use Committee of Guangzhou Medical University (2015-108).
The authors declare that they have no competing interests.
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