2004—2014年重庆市三峡库区县和非三峡库区县流行性乙型脑炎流行特征分析

Epidemiology of Japanese encephalitis in counties in three gorges reservoir area and non-three gorges reservoir area,Chongqing,2004-2014

目的分析2004 2014年重庆市流行性乙型脑炎（乙脑）流行病学特征,初步了解三峡库区县和非三峡库区县乙脑的发病特征,为乙脑预防控制措施的制定提供参考依据。方法收集＂全国传染病信息报告系统＂乙脑发病数据,采用描述流行病学方法,将重庆市分为三峡库区县和非三峡库区县,按2008年乙脑疫苗纳入计划免疫前后（2004 2008年、2009 2014年）分段进行乙脑发病特征的分析比较。结果重庆市三峡库区县和非库区县乙脑年均发病率分别为0.82/10万和1.12/10万,病死率分别为3.25%和2.82%。11年间两地区发病率变化趋势相同,病例中男性均多于女性,发病均集中在7 8月,均以15岁以下病例为主（98.77%）。库区县乙脑发病率从2004 2008年的1.34/10万降至2009 2014年的0.36/10万,非库区县的发病率从1.62/10万降至0.68/10万,库区县下降幅度明显大于非库区县（P〈0.01）。疫苗常规接种前后非库区县的病死率分别为3.96%和0.45%,而库区县病死率分别为3.54%和2.36%。疫苗常规免疫后,0~14岁各年龄组发病率库区县除3岁和4岁年龄组外均低于0.05/10万,非库区县均低于0.10/10万。结论重庆市三峡库区县与非库区县11年间乙脑发病趋势及季节分布与全国相近。2008年乙脑疫苗常规免疫后库区县0~14岁组发病率显著下降,提示三峡水库周边环境因素对乙脑发病未造成明显影响,库区县乙脑疫苗预防措施取得明显成效,但仍需加强易感人群保护及病例救治工作。

Objective To understand the epidemiological characteristics of Japanese encephalitis（ JE） in Chongqing during2004- 2014,and provide evidence for JE prevention and control. Methods The Descriptive epidemiological analysis was conducted by using the incidence data of JE in the counties in and outside three gorges reservoir area（ TGRA） in Chongqing during the periods before（ 2004- 2008） and after（ 2009- 2014） the inclusion of JE vaccination in immunization program.Results From 2004 to 2014,the average incidence of JE was 0. 82 / lakh in TGRA counties and 1. 12 / lakh in non-TGRA counties,and the case-fatality rate was 3. 25% and 2. 82%,respectively. The incidence trends of JE in TGRA counties and in non-TGRA counties were similar,and more cases occurred in males than in females. The cases were mainly reported during July-August,and most cases were aged 〈 15 years（ 98. 77%）. In TGRA counties,the JE incidence decreased from 1. 34 /lakh during 2004- 2008 to 0. 36 / lakh during 2009- 2014. In non-TGRA counties,the JE incidence decreased from 1. 62 / lakh during 2004- 2008 to 0. 68 / lakh during 2009- 2014,the difference was significant（ P〈0. 01）. In non-TGRA counties,the case fatality was 3. 96% during 2004- 2008 and 0. 45% during 2009- 2014,and in TGRA counties,the case fatality was3. 54% during 2004- 2008 and 2. 36% during 2009- 2014. After routine JE immunization,the incidence of JE in age group0-14 years in TGRA counties were lower than 0. 05 / lakh except age groups 3 years and 4 years,but the incidence of JE in age group 0-14 years in non-TGRA counties were lower than 0. 10 / lakh. Conclusion The incidence pattern and seasonal distribution of JE in Chongqing（ both in TGRA counties and in non-TGRA counties） were similar to national ones. After routine JE immunization,the incidence of JE in age group 0-14 years declined significantly in TGRA counties,suggesting that the environmental change in TGRA had no obvious impact on JE incidence and the JE immunization measure was effective,but improvements are still needed to protect risk populations.