广州市甲型H1N1流感流行初期疫情特点分析

Study on the epidemiological characteristics of early stage of novel influenza A (H1N1) in Guangzhou

目的总结广州市甲型H1N1流感流行特点,为预防控制提供参考。方法从三间分布、本地病例与输入性病例特点、感染场所、暴发疫情特点、临床表现、流行病学史、发现方式等特征分析广州市2009年5-7月网络直报的173例实验室确诊病例。结果本地病例97例（56.1%）,输入性病例76例（43.9%）。男性104例（60.1%）,女性69例（39.9%）。年龄为6个月至71岁,中位数为18.4岁。本地病例感染场所主要为学校,占64.9%。输入性病例中60.5%为散发病例,而本地病例中23.7%为散发病例,以聚集性为主,两类病例流行形式差异有统计学意义（χ2=24.9,P〈0.001）。临床表现以发热（≥37.5℃）（94.6%）、咳嗽（63.1%）,咽痛（40.3%）为主。8.7%病例出现消化道症状。47.0%的病例与有明确类症状病人接触史。输入性病例发病至确诊时间比本地病例要短（t=2.791,P=0.006）,发病至首次就诊时间间隔也比本地病例短（t=2.059,P=0.041）。输入性病例主要为出入境检验检疫发现（72.4%）,本地病例主要为自行就诊发现（46.4%）。结论广州市仍处于甲型H1N1流感流行初期。部分甲型H1N1流感病例有消化道症状,提示消化道传播的可能性需要关注。

Objective To analyze the epidemiological characteristics of novel influenza A（H1N1） and provide strategies for the disease prevention and control in future.Methods H1N1 influenza cases were confirmed by laboratory testing and reported by disease reporting information system from May to July,2009.We analyzed the H1N1 influenza case distribution,case source of origins（imported and indigenous）,suspected place of infection,outbreak characteristics,symptoms,epidemiological history,and etc.Results There were 97（56.1%） indigenous and 76（43.9%） imported cases reported in Guangzhou from May to July,2009.Of the confirmed cases,104（60.1%）were male and 69（39.9%） were female.The patients were aged from 0.5 to 71 years old with a median of 18.4 years old.Most indigenous cases were infected in school.Sporadic occurrences represented 60.5%（46/76） of imported cases,while clustering occurrences happened in 76.3%（74/97） of indigenous cases.The difference was statistically significant（χ2=24.9,P0.001）.Major symptoms were reported as fever（≥37.5℃）（94.6%）,cough（63.1%）,sore throat（40.3%）and etc.8.7% of the cases had intestinal tract symptoms.47.0% of the cases had exposure history of H1N1 influenza patients.The time from onset of the influenza symptoms to the first clinical visit in imported cases was shorter than that in indigenous cases（t=2.059,P=0.041）.72.4%（55/76） of imported cases were found by entry-exit inspection and quarantine while 46.4%（45/97）of indigenous cases were found by doctors′ consultation.Conclusion Guangzhou was still in early stage of novel influenza A（H1N1）.Intestinal tract symptoms were special in new H1N1 influenza virus infection.