Liu Yu-Fu, Lai Han-Zhang, Li Lin, Liu Yu-Peng, Zhang Wen-Yan, Gao Ren, Huang Wen-Ke, Luo Qin-Fang, Gao Yan, Luo Qiong, Xie Xiao-Yu, Xu Jia-Hua, Chen Rui-Ai
A College of Veterinary Medicine, South China Agricultural University, 483 Wushan Street, Tianhe District, Guangzhou, Guangdong Province, 510642, China.
B Key Laboratory of Biotechnology and Bioproducts Development for Animal Epidemic Prevention, Ministry of Agriculture, P. R. China, Guangdong Wens Dahuanong Biotechnology Co., Ltd., No. 6 Dongdi North Road, Xincheng Town, Xinxing County, Yunfu City, 527400, China.
Avian Dis. 2016 Dec;60(4):817-825. doi: 10.1637/11452-061616-Reg.
Forty-two H9N2 subtype AIV strains were isolated from vaccinated commercial chickens in China from 2012 to 2015. Their HA genes had nucleotide sequence homology from 86.7% to 99.7%, and similarity to the classic vaccine strain was 88.6%-92.6%. A comparison was carried out with published HA genes (410 H9 strains) and whole genomes (306 strains) isolated in China during 2012-2015. Interestingly, 99.1% (448/452) of Chinese H9N2 AIV belonged to lineage h9.4.2, and 98.5% (445/452) of the viruses belonged to h9.4.2.5. Meanwhile, 99.6% (443/445) of lineage 9.4.2.5 viruses had PSRSSR↓GLF instead of PARSSR↓GLF motifs in the HA cleavage sites; 98.2% (444/452) of HA genes showed human receptor binding associated mutation Q226L. A total of 96.8% (337/348) of the viruses had three amino-acid deletions at 63-65 in the NA stalk, associated with enhanced virulence in chickens and mice; 97.1% (338/348) of M2 proteins had the S31N mutation associated with adamantane resistance in humans. Two H9 viruses isolated in this study were highly homologous to the human-origin H9N2 virus reported in 2013. The isolates were divided into four different genotypes (U, S, V, and W). Genotype S was the major one, accounting for 94.8% (330/348). Genotypes V and W were new reassortment genotypes, with genotype W recombined with the PB2 gene originating from the new wild waterfowl-like lineage. According to the cross-HI antibody titer data, HA gene evolution, and isolation history, the isolates were divided into A, B, and C antigenic groups successively. All the antigenic group viruses were found to circulate throughout China. This study emphasizes the importance of updated vaccine and strengthened veterinary biosecurity on poultry farms and trade markets.
2012年至2015年期间，从中国接种疫苗的商品鸡中分离出42株H9N2亚型禽流感病毒（AIV）毒株。它们的血凝素（HA）基因核苷酸序列同源性为86.7%至99.7%，与经典疫苗株的相似性为88.6% - 92.6%。将其与2012 - 2015年期间在中国分离的已发表HA基因（410株H9毒株）和全基因组（306株）进行了比较。有趣的是，99.1%（448/452）的中国H9N2 AIV属于h9.4.2谱系，98.5%（445/452）的病毒属于h9.4.2.5。同时，9.4.2.5谱系病毒中99.6%（443/445）在HA裂解位点具有PSRSSR↓GLF而非PARSSR↓GLF基序；98.2%（444/452）的HA基因显示出与人受体结合相关的突变Q226L。共有96.8%（337/348）的病毒在神经氨酸酶（NA）柄的63 - 65位有三个氨基酸缺失，这与鸡和小鼠的毒力增强有关；97.1%（338/348）的M2蛋白具有与人金刚烷抗性相关的S31N突变。本研究中分离的两株H9病毒与2013年报告的人源H9N2病毒高度同源。这些分离株分为四种不同的基因型（U、S、V和W）。基因型S是主要类型，占94.8%（330/348）。基因型V和W是新的重配基因型，其中基因型W与源自新的野生水禽样谱系的PB2基因重配。根据交叉血凝抑制（HI）抗体效价数据、HA基因进化和分离历史，分离株依次分为A、B和C抗原组。发现所有抗原组病毒在中国各地传播。本研究强调了更新疫苗以及加强家禽养殖场和贸易市场兽医生物安全措施的重要性。
