从我国人群中再次分离到H9N2亚型流感病毒

A strain of influenza A H9N2 virus repeatedly isolated from human population in China

目的 了解分离流感病毒毒株表面抗原亚型和特性及其来源。方法 病毒通过MDCK细胞分离 ,用红细胞凝集抑制 (HI)和神经氨酸酶抑制 (NI)测定对病毒株表面抗原进行鉴定和特性分析 ,人血清中抗体测定采用HI和中和实验。对患者进行个案调查。结果 分离物为甲型流感病毒H9N2亚型 ,属G9类似毒株 ,它的HA抗原特性与已经从人、鸡和鸽分离到的H9N2亚型毒株均有差异。患者恢复期血清对分离物的HI抗体滴度为 40 0 ,中和效价为≥ 6 40。其母血清的HI滴度为 1:2 5。结论 从患者所分离出的病毒为H9N2亚型流感病毒 ,属G9类毒株。它的HA抗原性与测定的H9N2毒株均存在差异。

Objective To understand the subtype of surface proteins (haemagglutinin and neuraminidase) and antigenic character of the isolate of Infuluenza virus, as well as to know its origin.Methods The virus isolation was performed on MDCK cells.The identification and antigenic analysis of the isolate were carried out with HI and NI tests.The serum antibody in population against the isolate was detected with HI and neutralization assays.The individual investigation of the patient from whom the H9N2 virus was isolated was followed.Results The isolate was H9N2 subtype of influenza A virus.It was G9 like strain.Its antigenicity was different from that of H9N2 viruses which were previously found in humans,chickens and pigeons.The HI and neutralization titers to H9N2 virus in convalescent serum of the patient reached 1∶400 and ≥1∶640, respectively. The HI antibody titer 1∶25 to H9N2 virus was also detected in the serum of patient's mother.Conclusion The isolate is H9N2 subtype of influenza A virus and belonges to G9 like strain.The antigenic character of the isolate was different from that of H9N2 viruses found previously in humans,chickens and pigeons.The greatest possibility was that her mother had contacted with birds,especially chickens carrying H9N2 virus,then transmitted to her or she breathed in the air borne with H9N2 virus particles directly.