1949-2018年石家庄市流行性乙型脑炎发病趋势分析

目的 分析流行性乙型脑炎(简称乙脑)流行特征的长期趋势。方法 对石家庄市疫情资料汇编((1949-2018年)、国家传染病报告信息管理系统(2004-2018年)与急性脑炎脑膜炎监测合作项目(2007-2018年)中的乙脑资料,采用年度变化百分比(annual percent change,APC)和圆形分布定量评估乙脑疫情变化特征。结果 1949-2018年,石家庄市累计报告乙脑病例5 884例,病死率为19.02%。职业中,农民占51.16%。2001-2018年,流动人口病例占40.85%。年发病率范围为0.03/10万~72.43/10万,年均发病率1.72/10万,APC为-2.57(t=6.38,P<0.001)。1949-1993年的1~14岁病例占62.59%,而2016-2018年的50岁及以上病例占76.56%。每20年左右出现一次明显的流行高峰。病例主要集中在7-9月份。1949-1999年的发病高峰为8月24日(8月1日-9月17日)(z=4712.17,P<0.001),2000-2018年的发病高峰为8月6日(7月18日~10月25日)(z=146.10,P<0.001),两阶段的发病高峰期差异具有统计学意义(t=2.03,P<0.05)。结论 石家庄市乙脑疫情明显下降,高发人群年龄呈上升趋势,流动人口成为新的易感人群,严格的季节性发病高峰特征有所减弱,高峰日提前,高峰期间增宽。

Epidemic trend of Japanese encephalitisin in Shi Jiazhuang City,China,1949-2018

The aim of this study is to analyze the trends over time in Japanese encephalitis(JE) using the pre-existing data in Shi Jiazhuang. The laboratory-confirmed and clinical-confirmed JE cases that occurred during 1949-2018 were extracted from Shi Jiazhuang epidemic compilation (1949-2018), National Notifiable Disease Information Reporting System(2004-2018) and Acute Meningitis and Encephalitis Syndrome Surveillance Project(2007-2018). The annual percent change (APC) in incidence and circular distribution method were performed to demonstrate the secular trends. And APC was estimated using linear regression analysis of the natural logarithm for the annual incidence. In 1949-2018, 5884 JE cases were reported in Shi Jiazhuang. 1119 death cases were found, with fatality rate of 19.02%. Farmers accounted for 51.16% of JE cases. Ratio of floating population was 40.85% of JE cases in 2001-2018. The range of annual incidence rate was changed from 0.03/lakh to 72.43/lakh with annual incidence of 1.72/lakh and APC of -2.57(t=6.38,P<0.001). Ratio of JE cases aged 1~14 years was 62.59% in 1949-1994, while in 2016-2018, cases aged 50 years and above was up to 76.56% of JE cases. The epidemic peak occurred each about 20 years. The time distribution was mainly in July, August, and September. The analysis of circular distribution method showed that the peak period of incidence changed from August 24th (August 1st ~ September 17th) in 1949-1999 (z=4712.17,P<0.001) to August 6th (July 18th~October 25th) in 2000-2018(z=146.10,P<0.001). There was significant difference on the peak between the period of 1949-1999 and that of 2000-2018(t=2.03,P<0.05). In conclusion, there was a remarkable declined incidence of JE in Shi Jiazhuang. The risk population of JE moves from younger children to the aged population. Floating population has becoming one of the susceptible population. The peak day has been occurred earlier and the duration of peak period has been broadening than before.