Phylogenetic and Molecular Characterization of H9N2 Influenza Isolates from Chickens in Northern China from 2007-2009
Phylogenetic and Molecular Characterization of H9N2 Influenza Isolates from Chickens in Northern China from 2007-2009
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2007-2009年中国北方鸡H9N2流感分离株的系统发育和分子特征
DOI：
10.1371/journal.pone.0013063
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发表时间：
2010-09-29
期刊：
影响因子：
3.7
通讯作者：
Qiao, Jian
中科院分区：
文献类型：
--
作者：
Bi, Jianmin;Deng, Guangcun;Qiao, Jian
H9 N2病毒在中国的反复传播以及在陆地家禽中的长期流行性，使其生态学和致病性的研究变得迫切。本文报道了2007 - 2009年从我国北方地区鸡群中分离到的一株H9 N2亚型病毒对小鼠具有高致死性。全基因组系统发育分析表明，6株代表性H9 N2分离株之间具有较高的同源性，与北方地区近年分离的H9 N2病毒属同一亚系。分离株为双耐毒株，其M基因与A/Quail/Hong Kong/G1/97（H9 N2）相似，其它7个基因片段与A/Chicken/Shanghai/F/98（H9 N2）相似。这6个分离株能够在感染鸡的肺中复制，而不产生可观察到的疾病或死亡的临床体征。然而，它们对没有预先适应的小鼠具有高度致死性，死亡率高达100%（14/14）。受影响的小鼠表现出严重的呼吸综合征和弥漫性肺损伤。H9 N2病毒可以在受感染小鼠的多个器官中检测到，包括心脏、肝脏、脾脏、肺和肾脏。结果表明，我国北方鸡群中分离的H9 N2病毒已形成稳定的亚系，且对小鼠的致病性增强，提示H9 N2病毒从鸡到哺乳动物的传播应引起高度重视。
The repeated transmission to pigs and humans, and the long-term endemicity in terrestrial poultry of H9N2 viruses in China lend urgency to the study of their ecology and pathogenicity. In the present paper, we reported an H9N2 virus sublineage isolated from chickens in northern China from 2007 to 2009 has high lethality for mice. Phylogenetic analysis of the full genome indicated that six representative H9N2 isolates shared high homology to each other, and they clustered in the same sublineage with other H9N2 viruses isolated recently in northern China. The isolates were double-reassortant viruses containing M genes similar to A/Quail/Hong Kong/G1/97 (H9N2) and the other seven gene segments from A/Chicken/Shanghai/F/98 (H9N2). These six isolates were capable of replicating in the lungs of infected chickens without producing observable clinical signs of disease or death. However, they were highly lethal to mice with mortality rates as high as 100% (14/14) without prior adaptation. The affected mice exhibited severe respiratory syndromes and diffuse lung injury. The H9N2 viruses could be detected in multiple organs of the infected mice, including hearts, livers, spleens, lungs and kidneys. Our findings demonstrated that H9N2 viruses isolated from the chickens in northern China have established a stable sublineage with enhanced pathogenicity to mice, suggesting that urgent attention will need to be paid to the transmission of H9N2 viruses from chickens to mammals.