北京市首例人禽流感H5N1病例的感染来源调查

Investigation on the source of the first human of avian influenza A （H5N1 ） case in Beijing

目的渊查北京市首例人禽流感（H5N1）病例的感染来源。方法通过对患者家属和其他关键人物访谈，检测患者标本以及流行病学关联的环境标本，对患者可能的感染来源进行追踪调查。结果该患者在其发病前5天曾经接触过宰杀的鸭子（购自河北省燕郊某市场活禽摊位），采集该摊位及邻近活禽摊位的环境标本10份，经PCR方法检测有6份标本为H5N1亚型病毒核酸阳性，并通过鸡胚分离出5株H5N1亚型病毒。将从环境标本中分离的H5N1亚型病毒与患者体内分离的H5N1亚型病毒（禽源、属于Clade2．3．4）进行全基因组序列比对，氨基酸同源性高达99．8％-100％。结论流行病学和病原学双重证据表明，北京市首例人禽流感H5N1病例的感染来源为接触携带H5N1亚型禽流感病毒的鸭子。

Objective To investigate the source of the first human case of avian influenza A （H5N1） infection in Beijing. Methods Interviewing the relatives of the case and other key persons, collecting and detecting samples of related biological, epidemiological and environmental data of the case were conducted. Later, the infection source was thoroughly investigated. Results The case ever contacted a slaughtered duck 5 days prior to the onset of illness, and the duck was bought from a stall of a wet market in Yanjiao area of Hebei province. Ten environmental samples were collected in this stall and the neighboring stall of the market. Another 6 samples were tested positive for H5N1 virus by PCR method, with 5 virus strains isolated. The whole-genome sequencing indicated that the amino acid homology between the H5N1 virus strains from the environment and the virus isolated from the case reached 99.8%-100%. Conclusion From both epidemiological and virological evidence, it was proved that the first human case of avian influenza A （H5N1） infection in Beijing was infected by a duck that carrying H5N1 virus the case contacted 5 days proceeding the onset of illness.