Genesis and Spread of Newly Emerged Highly Pathogenic H7N9 Avian Viruses in Mainland China

作者：Lei Yang, Wenfei Zhu, Xiyan Li, Minmei Chen, Jie Wu, Paul B. Yu, Shunxiang Qi, Yiwei Huang, Weixian Shi, Jie Dong, Xiang Zhao, Weijuan Huang, Zi Li, Xiaoxu Zeng, Bo Hong, Tao Chen, Wenbing Chen, Jia Liu, Ye Zhang, Zhenli Liang, Wei Shi, Yuelong Shu, Dayan Wang · 发表于：Journal of Virology · 年份：2017 · DOI：10.1128/jvi.01277-17 · 被引用次数：136 · 研究领域：Influenza Virus Research Studies、Viral gastroenteritis research and epidemiology、Animal Virus Infections Studies

ABSTRACT The novel low-pathogenic avian influenza A H7N9 viruses (LPAI H7N9 viruses) have been a threat to public health since their emergence in 2013 because of the high rates of mortality and morbidity that they cause. Recently, highly pathogenic variants of these avian influenza A H7N9 viruses (HPAI H7N9 viruses) have emerged and caused human infections and outbreaks among poultry in mainland China. However, it is still unclear how the HPAI H7N9 virus was generated and how it evolved and spread in China. Here, we show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region and spread southward to the Pearl River Delta region, possibly through live poultry trade. After introduction into the Pearl River Delta region, the origin LPAI H7N9 virus acquired four amino acid insertions in the hemagglutinin (HA) protein cleavage site and mutated into the HPAI H7N9 virus in late May 2016. Afterward, the HPAI H7N9 viruses further reassorted with LPAI H7N9 or H9N2 viruses locally and generated multiple different genotypes. As of 14 July 2017, the HPAI H7N9 viruses had spread from Guangdong Province to at least 12 other provinces. The rapid geographical expansion and genetic evolution of the HPAI H7N9 viruses pose a great challenge not only to public health but also to poultry production. Effective control measures, including enhanced surveillance, are therefore urgently needed. IMPORTANCE The LPAI H7N9 virus has caused five outbreak waves in humans...