National Institute for Viral Disease Control and Prevention, Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health and Family Planning Commission, Beijing 102206, P.R. China.
National Institute for Viral Disease Control and Prevention, Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory for Medical Virology, National Health and Family Planning Commission, Beijing 102206, P.R. China; School of Public Health (Shenzhen), Sun Yat-sen University, Guangdong 510275, P.R. China.
Cell Rep. 2018 Apr 17;23(3):909-917. doi: 10.1016/j.celrep.2018.03.081.
The 2016-2017 epidemic of influenza A (H7N9) virus in China prompted concern that a genetic change may underlie increased virulence. Based on an evolutionary analysis of H7N9 viruses from all five outbreak waves, we find that additional subclades of the H7 and N9 genes have emerged. Our analysis indicates that H7N9 viruses inherited NP genes from co-circulating H7N9 instead of H9N2 viruses. Genotypic diversity among H7N9 viruses increased following wave I, peaked during wave III, and rapidly deceased thereafter with minimal diversity in wave V, suggesting that the viruses entered a relatively stable evolutionary stage. The ZJ11 genotype caused the majority of human infections in wave V. We suggest that the largest outbreak of wave V may be due to a constellation of genes rather than a single mutation. Therefore, continuous surveillance is necessary to minimize the threat of H7N9 viruses.
2016-2017 年中国发生的甲型 H7N9 流感疫情引发了人们的担忧，即基因的改变可能是导致病毒毒力增强的原因。基于对来自所有五次暴发浪潮的 H7N9 病毒的进化分析，我们发现 H7 和 N9 基因出现了更多的亚分支。我们的分析表明，H7N9 病毒从流行的 H7N9 病毒而不是 H9N2 病毒继承了 NP 基因。H7N9 病毒的基因型多样性在第一波之后增加，在第三波达到峰值，此后迅速下降，第五波的多样性最小，表明病毒进入了一个相对稳定的进化阶段。ZJ11 基因型在第五波引起了大多数人类感染。我们认为，第五波最大的暴发可能是由于多种基因的共同作用，而不是单一突变。因此，有必要进行持续监测，以最大限度地减少 H7N9 病毒的威胁。
