北京市大兴区首例人感染H7N9禽流感病例的流行病学调查

目的分析北京市大兴区首例人感染H7N9禽流感确诊病例的流行病学特征,为人感染H7N9禽流感科学防控提供依据。方法采用现场流行病学调查方法,了解病例的发病就诊情况、可能的感染来源、传播途径和暴露因素等;对可疑共同暴露者及密切接触者采取医学观察,开展强化监测及进一步扩大溯源监测等工作;采用实时荧光定量聚合酶链式反应(Real-time PCR)进行甲型流感通用引物及H7N9禽流感病毒核酸检测。结果该病例为北京市大兴区首例人感染H7N9禽流感确诊病例,经治疗后痊愈出院;病例有明确的禽类接触史,确定共同暴露者及密切接触者共7人,实验室检测均未发现H7N9禽流感病毒。强化监测共报告流感样病例(ILI)病例594例,严重急性呼吸道感染(SARI)病例21例,采集咽拭子标本615件,均为H7N9禽流感病毒核酸阴性。溯源扩大监测共采集咽拭子标本176件,其中1件活禽散养户外环境涂抹、3件鸡咽拭子标本检测出H7N9禽流感病毒核酸阳性,其余均为阴性。结论活禽暴露史是该病例感染的关键风险因素,提示存在"禽-人"或"禽-环境-人"传播方式。应加强H7N9禽流感防治知识的宣传教育,有效控制疫情的发生发展。

Epidemiological investigation of the first case of human infection with avian influenza A(H7N9)virus in Daxing District of Beijing

Objective]To analyze the epidemiological characteristics of the first case of human infection with avian influenza A(H7N9)virus in Daxing District of Beijing,provide scientific basis for prevention and control of human H7N9 avian influenza.Methods]The field epidemiological investigation was used to investigate the incidence of the disease,the possible source of infection,the route of transmission and the factors of exposure.Medical observation was carried out for suspected co-exposures and close contacts,while intensified monitoring and further expanded traceability monitoring were carried out.The influenza A universal primers and H7N9 avian influenza virus nucleic acid were detected by Real-time PCR.Results]The case was confirmed as the first case of human infection with avian influenza A(H7N9)virus in Daxing District of Beijing,and the patient was cured and discharged after treatment.The patient had a clear history of avian contact.There were seven co-exposures and close contacts,and the avian virus was not found by the laboratory testing.The intensive surveillance reported 594 cases of influenza like illness(ILI)and 21 cases of severe acute respiratory infection(SARI),and collected 176 pharyngeal swabs,while all were negative for the H7N9 avian virus nucleic acid.The expanded traceability monitoring collected 615 pharyngeal swabs,and one external environment smearof live poultry and three chicken throat swabs were positive for H7N9 avian influenza virus nucleic acid,while the rest swabs were negative.Conclusion]History of live poultry exposure is a key risk factor for infection in this case,suggesting the existence of birds-human transmission or birds-environment-human transmission.It is necessary to strengthen the publicity and education on prevention and treatment of avian influenza to effectively control the occurrence and development of the epidemic.