我国H7N2亚型禽流感病毒CK/HB/1/02株分离鉴定

从鸡组织中获得了一株分离物,能凝集鸡红细胞,经负染后电镜观察可见球形、外被囊膜的病毒颗粒,直径约 90～100nm;经血凝抑制和神经氨酸酶抑制试验鉴定为H7N2亚型禽流感病毒(Avian influenza virus,AIV),命名 为A／Chicken／Hebei／1／2002(H7N2)(简称CK／HB／1／02)。将该病毒接种SPF鸡,测得静脉接种致病指数(IVPI) 为0．00,剖检可见实验鸡多种组织器官有出血性变化,判为低致病力AIV;接种后7d从实验鸡泄殖腔棉拭中回收 到病毒,并在血清中检测到H7亚型AIV抗体。经RT-PCR扩增了病毒HA1基因片段(约1．1kb),测定其核苷酸 序列并与GenBank中的序列比较。结果表明,该病毒的HA1基因序列与AIV标准株A／Afri．Star．／Eng-Q／79 (H7N1)的HA1基因同源性最高,为99．4％;与以色列和意大利H7N2 AIV的同源性较高,为96．8％～98．2％;与 美国H7N2病毒的同源性很低,约为81．0％;其HA裂解位点的氨基酸序列为-KGR-GLF-,符合低致病力AIV的 特征。

Isolation and Identification of H7N2 Avian Influenza Virus Strain CK/HB/1/02 in China

A virus isolate from domestic chicken agglutinated chicken erythrocytes and was found as globular enveloped virion of 90nm-100nm diameters under TEM. The isolate was identified as H7N2 Avian influenza virus(AIV) by HI and NI assays and designated as A/Chicken/Hebei/1/ 2002(H7N2,or briefly as CK/HB/1/02. After inoculating to SPF chicken, the virus was recovered from cloacal swabs and the antibody to H7 was detected at 7 days post-infection (DPI). The IVPI was 0. 00 and postmortem examination showed hemorrhages in several tissues and organs indicating that the virus was LPAIV. HA gene of the isolate exhibited 99. 4% nucleotide sequence identity to A/Afri. Star. /Eng-Q/79(H7N1) virus, 96. 8%-98. 2% to H7N2 virus isolated from Italy and Israel, and only about 81. 0% to American H7N2 Strain. The amino acid at the cleavage site of HA is -KGR-GLF-, which implies the isolate should be of low pathogenicity.