贵州省健康人群流行性乙型脑炎血清流行病学调查

目的 调查贵州省健康人群流行性乙型脑炎（乙脑）中和抗体水平。方法 采用分层随机抽样的方法，在乙脑流行季节采集6个市（州）8个年龄组健康人群血清共960份，应用蚀斑减少中和试验法检测乙脑中和抗体。结果 960名调查对象中乙脑中和抗体阳性率为64.69%，几何平均滴度（GMT）为1∶30.32。男、女性乙脑中和抗体阳性率分别为59.82%、68.77%（χ2 = 8.364, P = 0.004）；不同年龄乙脑中和抗体阳性率在52.50%～84.17%之间（χ2 = 35.893, P＜0.001），GMT在1∶20.00～1∶41.40之间（χ2 = 22.207, P = 0.002），其中中和抗体阳性率最低为＜ 1岁组，最高为＞40岁组，GMT最低为11～15岁组，最高为＞40岁组；不同地区乙脑中和抗体GMT在1∶18.62～1∶43.66之间（χ2 = 56.581, P＜0.001）。结论 贵州省健康人群乙脑中和抗体水平总体较低，应加强乙脑监测，提高人群免疫水平，尤其是应加强对学龄儿童和青少年的免疫接种工作。

Epidemiological survey of Japanese encephalitis in healthy population from Guizhou province

Objective The aim of this study was to investigate the level of neutralizing antibodies against Japanese encephalitis (JE) virus in healthy population from Guizhou province. Methods A stratified random sampling method was used to collect 960 serum samples of healthy population in 8 age groups from 6 cities(states) during the epidemic season of JE. Neutralizing antibodies against Japanese encephalitis virus of healthy population were detected by plaque reduction neutralization test. Results The positive rate of neutralizing antibodies against Japanese encephalitis virus was 64.69%, and the geometric mean titer (GMT) was 1:30.32 in 960 subjects. The positive rates of neutralizing antibodies against Japanese encephalitis virus in male and female health population were 59.82% and 68.77% respectively(χ2=8.364, P=0.004). The positive rates and GMT of neutralizing antibody against JE virus among healthy population of different age groups were from 52.50% to 84.17% (χ2=35.893, P<0.001) and from 1:20.00 to 1:41.40 (χ2=22.207, P=0.002), respectively. The positive rates of neutralizing antibodies against JE in the age group of <1 and 11-15 years were lower, and in the age group of >40 years was the highest. And the GMT in the age group of 11-15 years was the lowest, while that in the age group of >40 years also was the highest. The GMT of neutralizing antibody against JE virus among healthy population from different regions was between 1:18.62 and 1:43.66(χ2=56.581, P<0.001). Conclusion This study indicated that the level of neutralizing antibodies against Japanese encephalitis virus of healthy population in Guizhou province was low. JE monitoring should be strengthened to improve the healthy population's immunization level, especially for school-age children and adolescents.