2010年河南省流行性乙型脑炎流行特点及健康人群病毒抗体水平

Epidemic characteristics and viral antibody level among healthy people of Japanese B encephalitis in Henan province in 2010

目的了解2010年河南省流行性乙型脑炎（乙脑）流行特点及健康人群乙脑病毒抗体水平。方法提取2010年河南省监测的433例乙脑患者资料，用描述流行病学方法对其进行分析。于2010年选取洛阳市和信阳市为调查点，采用整群分层抽样方法在两市各选择12个行政村（社区居委会），选择〈1、1～2、3～4、5～6、7～14、15～19、20～59和≥60岁8个年龄组健康人群作为调查对象，共519名。分别于2010年的5月和11月调查和采集同一人群血液标本，共1008份，用微量细胞中和试验检测乙脑病毒抗体。结果2010年河南省乙脑发病率为0．46／10万（433／94130434）。97．69％（423／433）的患者集中在7-9月；81．06％（351／433）的患者分布在南阳、信阳、洛阳、驻马店和周口市。河南省0～14岁人群乙脑发病占82．22％（356／433），≥15岁人群发病占17．78％（77／433）。洛阳市≥15岁人群乙脑发病占65．79％（50／76），明显高于河南省的17．78％（χ2=79．57，P〈0．05）。河南省乙脑发病以散居儿童为主，占58．89％（255／433），洛阳市以农民为主，占44．74％（34／76）。洛阳市≥15岁健康人群乙脑抗体阳性率为48．94％（46／94），低于信阳市的97．78％（88／90），差异有统计学意义（χ2=55．42，P〈0．05）。洛阳市健康人群中有免疫史者乙脑抗体阳性率为50．41％（61／121），高于无免疫史者的16．67％（6／36），差异有统计学意义（χ2=12．92，P〈0．05）。信阳市健康人群中有免疫史者乙脑抗体阳性率为67．11％（51／76），高于无免疫史者的46．39％（45／97），差异有统计学意义（χ2=7．40，P〈0．05）。结论河南省乙脑发病呈季节性、地域性，不同年龄、职业人群发病有差异。河南省与洛阳市乙脑发病年龄和职业的差异与二者健康人群乙脑抗体水平的差异相一致。

Objective To understand the epidemic characteristics and viral antibody level among healthy people of Japanese B encephalitis （ JE ） in Henan province in 2010. Methods A total of 433 selected JE cases in Henan province in 2010 were analyzed by descriptive epidemiological method. Xinyang and Luoyang were selected as survey sites in 2010. 12 administrative villages were randomly selected from both cities. As the investigation objects, 519 healthy people from the two cities were randomly selected by eight age groups ： less than one year old, 1 - 2 years old, 3 - 4 years old, 5 - 6 years old, 7 - 14 years old, 15 - 19 years old, 20 - 59 years old, and above 60 years old. A total of 1008 samples of blood specimens were collected both in May and November, and JE viral antibody was detected by microcytopathic effect neutralization test. Results The incidence rate of JE was 0.46/100 000 （ 433/94 130 434 ） in Henan province in 2010. 97.69% （423/433）of the patients were found between July and September, and 81.06% （351/433） were distributed in Nanyang, Xinyang, Luoyang, Zhumadian and Zhoukou city. Children aged 0 to 14 years were the primarily affected group （ 82. 22% , 356/433 ） , the people above 15 years oldaccounted for 17.78% （77/433） of whole cases in Henan province, but the same group accounted for 65.79% （50/76） of whole cases in Luoyang city, which obviously higher than the percentage in Henan provinee（χ2 = 79. 57, P 〈 0. 05 ）. Most patients were scattered children in Henan province, accounting for 58.89% （255/433）. In Luoyang city, most patients were peasants, accounting for 44.74% （34/76）. The antibody positive rate of JE among health people above 15 years old in Luoyang city was 48.94% （46/94） , which was lower than it in Xinyang city at 97.78% （88/90）. The difference showed statistical significance （χ2 = 55.42,P 〈 0. 05）. The antibody positive rate among healthy people under vaccination was 50.41% （61/121）, which was obviously higher than that among people without vaccination, at 16. 67% （6/36） in Luoyang city. The difference showed statistical significance （χ2 = 12. 92, P 〈 0. 05）. The antibody positive rate among healthy people under vaccination was 67. 11% （51/76）in Xinyang city, which was obviously higher than that among people without vaccination, at 46. 39% （45/97）. The difference showed statistical significance （χ2= 7.40, P 〈 0. 05 ） . Conclusion The incidence of JE showed seasonal and regional characteristics, there were differences among ages and occupations. The difference was consistent with the difference in viral antibody level mnong health people in Henan province and Luoyang city.