2012年房山区健康人群流行性乙型脑炎抗体水平调查

Japanese B encephalitis antibody level in healthy people in Fangshan District,2012

目的了解北京市房山区健康人群流行性乙型脑炎(乙脑)抗体水平及其分布特点,为采取有效的乙脑预防措施和控制策略提供科学依据。方法 2012年用容量比例概率抽样法在房山区随机选取10个村居委会,在当地连续居住6个月以上的10个年龄组人群作为研究对象,共260人。采用调查问卷收集研究对象人口学特征、含乙脑疫苗免疫史、乙脑患病史。采集静脉血5 ml,采用蚀斑减少中和试验法检测乙脑中和抗体。结果调查对象抗体阳性率为68.08%。不同性别、不同户籍研究对象间乙脑抗体阳性率差异无统计学意义(均P>0.05)。不同年龄组人群中,乙脑抗体阳性率差异有统计学意义(χ2=44.495,P<0.01)。<1岁组儿童乙脑抗体阳性率最低(17.39%)。丘陵地区人群乙脑抗体阳性率明显高于平原地区和山地地区(χ2=18.935,P<0.01)。无免疫史人群抗体阳性率明显低于有接种史和接种史不详的人群(χ2=36.875,P<0.01)。不同职业人群抗体阳性率差异有统计学意义(χ2=37.876,P<0.01)。结论 2012年北京市房山区健康人群感染乙脑病毒的概率和频次降低;及时接种乙脑疫苗对保护<1岁儿童具有重要作用,同时需警惕乙脑发病向大年龄人群推移。

Objective To study the antibody level of Japanese B encephalitis virus （ JEV ） and its distribution features among healthy people in Fangshan District, Beijing, and provide scientific immunization strategy for the elimination of Japanese B encephalitis （JE ）. Methods Totally, 260 residents of 10 age groups from 10 village neighborhood committees who had been living in Fangshan District in Beijing for over 6 months were recruited in the study by probability proportion to size sampling method. Demographic characteristics, histories of JE vaccine immunization and JE infection were investigated by questionnaires. 5 ml blood was collected from each subject. Neutralizing antibody of JEV was detected by plaque reduction neutralization test. Results The positive rate of JEV antibody was 68.08%. It was not significantly different either in gender or in census register（ P〉0.05）, but it was significantly different among different age groups （χ^2 =44.495, P〈0.01） , with the lowest in the 〈 1 year age group（ 17.39%）. It was significantly higher in hilly regions than in plain and mountain regions（χ^2= 18.935 ,P〈0.01）, and lower in population without vaccination history than in those with vaccination history or unknown vaccination history（χ^2= 36. 875 ,P〈0.01）. It was also significantly different among people with different professions （χ^2= 37.876 ,P〈0.01 ）. Conclusions The probability and frequency of healthy people infected with JEV is decreasing in Fangshan District, Beijing in 2012. Timely vaccination of Japanese B encephalitis vaccine is very important in protecting children younger than 1 year old. The evolvement of shift of Japanese B encephalitis virus infection incidence from children to adult should be concerned.