国内首起本地感染甲型H1N1流感疫情的流行病学分析

目的 分析周内首起甲型H1N1流感输入性传染源引发本地二代病例疫情,探讨发病规律和流行特征.方法 设计统一调查表,采用面对面病例个案调查和现场调查,以指示病例为起点进行追踪,描述传播过程及各因素与发病之间的关系,分析疫情的流行病学特征.结果 发现指示病例后,密切接触者中有2人出现发热和上呼吸道症状且咽拭子甲型H1N1流感病毒核酸检测阳性,被确诊为国内首起本地感染甲型H1N1流感病例.2名密切接触者未采取任何防护措施与指爪病例多次近距离接触,且现场通风不良;发病潜伏期37～57 h,临床表现均较指示病例轻.经采取严格防疫措施,未见新发病例.结论 此次事件为由输人性传染源引起的本地感染疫情,无防护近距离空气及飞沫传播为主要传播方式,空气流通不良的密闭空间是高危场所.

Epidemiological characteristic of first case of locally identified A/H1N1 secondary cases caused by imported source of infection in China

Objective To study the first locally identifcd A/HINI secondary cases outbreak in China. Methods Interview and field investigation were integrated to describe the whole process of transmission on each case and to illustrate the relationships between the onset of the disease and the retated factors. Results Two contact persons appearanced fever and whose throat swabs were tested positive to H1N1 viral nucleic acid. The two had a history of contact in a short distance with the initial imported case without any protective measure in the poor air ventilation. The patients clinical situation was slight. The incubation was between 37 hours and 57 hours. No other new case was found after intervention as isolation and antisepsis were taken. Conclusion This event was proved to be an outbreak of local A/H1N1 secondary cases caused by the imported case. The main mode of transmission was personal contact in a short distance without protection, through air and droplet. The locus with poor air ventilation was high risk place. Contact persons should be observed seven days and tested continuously.Infectivity and pathogenicity of the A/H1N1 virus were limited and appeared weakened by generations. Patient's condition was related with persistence and frequency of contact with the infection sources. Enhancing management of contact persons, health education, early diagnose, early treatment and early insulation were effective measures of controling and prenventing the spread A/H1N1.