新疆首例人感染H7N9禽流感病例流行病学调查

Epidemiological investigation on the first human case of avian influenza H7N9 in Xinjiang

目的分析新疆首例人感染H7N9禽流感病例流行病学特征,探讨该病例可能的感染来源,为新疆制定人感染H7N9禽流感防控措施提供依据。方法对一例不明原因肺炎病例展开现场流行病学调查,在病原学排查的同时对病例及其密切接触者和可疑感染来源进行流行病学调查,采集相关标本送实验室检测,并应用描述流行病学方法进行分析。结果该病例有明确的禽类养殖及无防护措施的禽排泄物及其污染环境暴露史,呼吸道标本检测出人感染H7N9禽流感病毒,相关外环境和家禽标本H7N9禽流感病毒核酸检测阳性,环境标本分离禽流感病毒与人标本中分离的禽流感病毒HA片段和NA片段同源性为99.9%和100.0%,未发现人与人之间传播病例。结论该病例为新疆确诊的首例人感染H7N9禽流感病例,传播途径可能为禽—环境—人或者禽—人;加强门诊医生诊断敏感性和强化不明原因肺炎监测工作是及时发现与处理人感染H7N9禽流感疫情的重要手段。

Objective To analyze the epidemiological characteristics of the first human case of avian influenza H7N9 infection in Xinjiang, explore the possible source of infection, and provide the basis for formulating prevention and control measures of human infection of avian influenza H7N9. Methods Field epidemiological investigation was carried out on a case of pneumonia of unknown reason. The etiological determination and the epidemiological survey were conducted in the case, close contacts and suspicious source of infection. The relevant specimens were collected for laboratory test and the results were analyzed with descriptive epidemiological method. Results This case had clear history of poultry cultivation, and exposure to poultry excreta and its pollution in the environment. H7N9 virus was detected in the respiratory tract specimens. The nucleic acid of H7N9 virus was positive from the samples of the poultry and external environment. The homology of HA and NA fragment of the avian influenza virus isolated from the environment samples and human samples was 99.9% and 100.0%, respectively. No case of human to human transmission was found. Conclusions This is the first case infected avian influenza H7N9 in Xinjiang, with the transmission route of avian-environment-human or avian-human. Improving the diagnostic sensitivity of outpatient doctors and strengthening the surveillance of unexplained pneumonia are the important measures to find and treat the epidemic of avian influenza H7N9 in time.