Yi Guan 及同事研究了最近在中国人群中出现的H7N9流感病毒的演化史。通过在流感爆发后不久所进行的实地监测，作者提供了若干新禽流感病毒的基因组：34个H7N7基因组、3个H7N9基因组和19个H9N2基因组、以及从在2000年和2013年间在中国南方收集到的存档分离菌种得到的197个序列。他们发现，H7病毒至少在两个独立场合可能是从鸭传给鸡的，与H9N2病毒的再分类产生了H7N9这个爆发类别以及另一个以前没有被识别出的H7N7类别。这些H7N7病毒在实验中能感染雪貂，而且虽然还没有什么证据证明这些病毒已适应了哺乳动物，但作者提出，目前的疫情威胁可能会超越H7N9病毒。(生物谷Bioon.com)
生物谷推荐的英文摘要
Nature doi:10.1038/nature12515
The genesis and source of the H7N9 influenza viruses causing human infections in China
Tommy Tsan-Yuk Lam, JiaWang, Yongyi Shen, Boping Zhou, Lian Duan, Chung-Lam Cheung, Chi Ma,Samantha J. Lycett, Connie Yin-Hung Leung, Xinchun Chen, Lifeng Li, Wenshan Hong, Yujuan Chai, Linlin Zhou,Huyi Liang, Zhihua Ou, Yongmei Liu, Amber Farooqui, David J. Kelvin, Leo L. M. Poon, David K. Smith1,Oliver G. Pybus7,8, Gabriel M. Leung1,3, Yuelong Shu9, Robert G. Webster10, Richard J. Webby10, Joseph S. M. Peiris,Andrew Rambaut, Huachen Zhu & Yi Guan
A novel H7N9 influenza A virus first detected in March 2013 has since caused more than 130 human infections in China, resulting in 40 deaths. Preliminary analyses suggest that the virus is a reassortant of H7, N9 and H9N2 avian influenza viruses, and carries some amino acids associated with mammalian receptor binding, raising concerns of a new pandemic. However, neither the source populations of the H7N9 outbreak lineage nor the conditions for its genesis are fully known. Using a combination of active surveillance, screening of virus archives, and evolutionary analyses, here we show that H7 viruses probably transferred from domestic duck to chicken populations in China on at least two independent occasions. We show that the H7 viruses subsequently reassorted with enzootic H9N2 viruses to generate the H7N9 outbreak lineage, and a related previously unrecognized H7N7 lineage. The H7N9 outbreak lineage has spread over a large geographic region and is prevalent in chickens at live poultry markets, which are thought to be the immediate source of human infections. Whether the H7N9 outbreak lineage has, or will, become enzootic in China and neighbouring regions requires further investigation. The discovery here of a related H7N7 influenza virus in chickens that has the ability to infect mammals experimentally, suggests that H7 viruses may pose threats beyond the current outbreak. The continuing prevalence of H7 viruses in poultry could lead to the generation of highly pathogenic variants and further sporadic human infections, with a continued risk of the virus acquiring human-to-human transmissibility.
