Cheung C L, Vijaykrishna D, Smith G J D, Fan X H, Zhang J X, Bahl J, Duan L, Huang K, Tai H, Wang J, Poon L L M, Peiris J S M, Chen H, Guan Y
State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Li Ka Shing Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong, SAR, China.
J Virol. 2007 Oct;81(19):10402-12. doi: 10.1128/JVI.01157-07. Epub 2007 Jul 25.
An H6N1 virus, A/teal/Hong Kong/W312/97 (W312), was isolated during the "bird flu" incident in Hong Kong in 1997. Genetic analysis suggested that this virus might be the progenitor of the A/Hong Kong/156/97 (HK/97) H5N1 virus, as seven of eight gene segments of those viruses had a common source. Continuing surveillance in Hong Kong showed that a W312-like virus was prevalent in quail and pheasants in 1999; however, the further development of H6N1 viruses has not been investigated since 2001. Here we report influenza virus surveillance data collected in southern China from 2000 to 2005 that show that H6N1 viruses have become established and endemic in minor poultry species and replicate mainly in the respiratory tract. Phylogenetic analysis indicated that all H6N1 isolates had W312-like hemagglutinin and neuraminidase genes. However, reassortment of internal genes between different subtype virus lineages, including H5N1, H9N2, and other avian viruses, generated multiple novel H6N1 genotypes in different types of poultry. These novel H6N1/N2 viruses are double, triple, or even quadruple reassortants. Reassortment between a W312-like H6N1 virus and an A/quail/Hong Kong/G1/97 (HK/97)-like H9N2 virus simultaneously generated novel H6N2 subtype viruses that were persistent in poultry. Molecular analyses suggest that W312-like viruses may not be the precursors of HK/97 virus but reassortants from an HK/97-like virus and another unidentified H6 subtype virus. These results provide further evidence of the pivotal role of the live poultry market system of southern China in generating increased genetic diversity in influenza viruses in this region.
1997年香港“禽流感”事件期间分离出一株H6N1病毒，即A/teal/Hong Kong/W312/97（W312）。基因分析表明，该病毒可能是A/Hong Kong/156/97（HK/97）H5N1病毒的祖先，因为这些病毒的八个基因片段中有七个具有共同来源。香港持续监测显示，1999年鹌鹑和雉鸡中流行一种类似W312的病毒；然而，自2001年以来尚未对H6N1病毒的进一步演变进行调查。在此，我们报告了2000年至2005年在中国南方收集的流感病毒监测数据，这些数据表明H6N1病毒已在小型家禽物种中定殖并成为地方病，主要在呼吸道中复制。系统发育分析表明，所有H6N1分离株都具有类似W312的血凝素和神经氨酸酶基因。然而，不同亚型病毒谱系（包括H5N1、H9N2和其他禽流感病毒）之间的内部基因重配，在不同类型的家禽中产生了多种新型H6N1基因型。这些新型H6N1/N2病毒是双重、三重甚至四重重配体。类似W312的H6N1病毒与A/quail/Hong Kong/G1/97（HK/97）样H9N2病毒之间的重配同时产生了在家禽中持续存在的新型H6N2亚型病毒。分子分析表明，类似W312的病毒可能不是HK/97病毒的前体，而是HK/97样病毒与另一种未鉴定的H6亚型病毒的重配体。这些结果进一步证明了中国南方活禽市场系统在该地区流感病毒遗传多样性增加中所起的关键作用。
