1972-2011年西双版纳州流行性乙型脑炎流行病学特征分析

Epidemiological analysis on epidemic encephalitis B in Xishuangbanna,1972-2011

目的分析西双版纳州40年来流行性乙型脑炎（乙脑）的流行趋势和流行病学特征，为制定防控策略提供依据。方法对西双版纳州1972—2011年乙脑疫情资料进行描述性分析。结果1972—2011年共报告乙脑病例1384例，死亡184例，年均发病率为4．86／10万，年均死亡率为0．73／10万，年均病死率为9．25％；1972—2001年的30年间，6～9月为流行季节，发病高峰为8月；2002—2011年的10年间，流行季节为5～8月，发病高峰前移至6月；发病以10岁以下儿童为主（占72．20％），职业分布以散居儿童和学生居多（占73．49％）；2007年发生近30来较为严重的一次乙脑暴发疫情，疫情波及全州2县1市，持续70余天，共报告病例75例，死亡6例，发病率为7．13／10万。结论西双版纳州为乙脑自然疫源性地和乙脑流行的高发区，存在境外输入病例和免疫空白人群，发病季节前移，存在局部暴发流行的隐患。

Objective To analyze the epidemic trend and characteristics of encephalitis B in Xishuangbanna dur- ing 40 years, so as to provide basis for developing prevention and control strategy. Methods The epidemic da- ta of Xishuangbanna from 1972 to 2011 were descriptively analyzed. Results A total of 1 384 encephalitis B cases from 1972 to 2011 were reported, including 184 death cases. The average annual incidence was 4.86/ 100 000, the annual mortality rate was 0.73/100 000, and the average fatality rate was 9.25%. During 1972 - 2001 , June to September were the popular seasons and August was the peak season. During 2002 - 2011 10 years, popular season for May to August, the peak season went forward to June. Disease cases concentrated in children under l0 years old （72. 20% ） Professional distribution mainly occupied scattered children and students （73.49%） . In 2007, an outbreak of encephalitis B occurred which was the most serious one during 30 years, and the epidemic spread to 2 counties and 1 municipality of Quanzhou which last more than 70 days. A total of 75 cases were reported, including 6 death cases, and the incidence was 7.13/100 000. Conclusions Xishuangbanna is the natural infectious and epidemic incidence area of encephalitis B, existing outside in- put cases and immunization blank group. Morbidity seasons go forward, which lead to the existence of local epidemic potential.