H7N9 avian influenza A virus in China: a short report on its circulation, drug resistant mutants and novel antiviral drugs

ABSTRACT

Introduction: The first human H7N9 avian influenza virus case was reported in Shanghai in 2013. Shortly thereafter, this virus spread to other regions in China. Molecular analysis indicated that the H7N9 virus is a reassortant virus containing internal genes from the H9N2 virus and previously described mammalian adaption markers, which could allow the virus to adapt efficiently to a mammalian host. Fortunately, there is no evidence of sustained person-to-person spread. Most of the human H7N9 cases have a history of exposure to live poultry markets (LPMs). The circulating H7N9 were low pathogenic viruses, however highly pathogenic H7N9 viruses were recently identified in human cases.

Areas covered: In the present article, the circulation of H7N9 in LPMs of China, the five waves of H7N9 infection in humans, recently identified drug resistant mutants and potential antiviral drugs against H7N9 are discussed; this may provide further understanding of the evolution and pandemic potential of the H7N9 influenza viruses.

Expert commentary: All the data reveal that the major source of H7N9 viruses are LPMs and the H7N9 virus is still circulating widely in China. It is concerning that the recent emergence of highly pathogenic H7N9 viruses may result in highly transmissible viruses in mammalian species.

KEYWORDS:

• H7N9
• drug resistant
• highly pathogenic influenza virus
• live poultry markets

Acknowledgments

We would like to thank JP Gonzalez for his critical comments on the manuscript.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This study was supported by the National Key Research and Development Plan (YFD0500204), National Natural Science Foundation of China (no. 31472206, no. 31402150 and no. 31572543), Chinese Academy of Agricultural Sciences Young Talent Scientist Program, and NIAID Center of Excellence for Influenza Research and Surveillance program, HHSN 266200700006C.