目的 分析1例人感染高致病性H7N9禽流感病例的感染模式及病原变异情况,为禽流感防控提供依据.方法 采用流行病学方法调查病例可疑暴露史及感染途径,追踪调查病例病情进展;使用核酸检测、病毒分离、基因测序及进化分析等技术对采集的相关标本展开病原学分析.结果 病例无活禽接触史,发病前一周在狭小通风不畅厨房内不带手套加工烹饪光鸡;病例下呼吸道提取物、病家剩余冷冻光鸡表面涂抹标本、活禽来源市场环境标本均检出高度同源的H7N9禽流感病毒,且均在HA基因的裂解位点出现多个碱性氨基酸(PEVPKRKRTAR/GL)插入的突变.结论 无防护禽肉操作是“禽-人”传播模式下的重要感染方式之一,现行的活禽限售区防控措施效果有限,应尽快推进规模化标准养殖,实现活禽全城限售、集中屠宰、冰鲜上市.%Objective To investigate the infection pattern and etiological characteristics of a case of human infection with highly pathogenic avian influenza A (H7N9) virus and provide evidence for the prevention and control of human infection with highly pathogenic avian influenza virus.Methods Epidemiological investigation was conducted to explore the case's exposure history,infection route and disease progression.Samples collected from the patient,environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (RT-PCR).Virus isolation,genome sequencing and phylogenetic analysis were conducted for positive samples.Results The case had no live poultry contact history,but had a history of pulled chicken processing without taking protection measure in an unventilated kitchen before the onset.Samples collected from the patient's lower respiratory tract,the remaining frozen chicken meat and the live poultry market were all influenza A (H7N9) virus positive.The isolated viruses from these positive samples were highly homogenous.An insertion which lead to the addition of multiple basic amino acid residues (PEVPKRKRTAR/GL) was found at the HA cleavage site,suggesting that this virus might be highly pathogenic.Conclusions Live poultry processing without protection measure is an important infection mode of "poultry to human" transmission of avian influenza viruses.Due to the limitation of protection measures in live poultry markets in Guangzhou,it is necessary to promote the standardized large scale poultry farming,the complete restriction of live poultry sales and centralized poultry slaughtering as well as ice fresh sale.
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