2012-2016年贵州省流行性乙型脑炎实验室监测病例特征分析

Analysis of the characteristics of cases of Japanese encephalitis in Guizhou Province from 2012-2016 based on laboratory monitoring

目的了解贵州省2012-2016年流行性乙型脑炎(简称乙脑)流行病学特征,为乙脑防控提供依据。方法采用ELISA法对贵州省2012-2016年乙脑疑似病例进行血和脑脊液乙脑IgM抗体检测,对病例资料进行分析。结果2012-2016年贵州省实验室检出乙脑疑似病例共1 317例,男女比2.3∶1;≤15岁1 275例,占96.81%。疑似病例标本分单份血清、单份脑脊液、血清和脑脊液双份3类,构成比分别为55.35%、6.61%、38.04%。不同类型标本乙脑IgM阳性率差异有统计学意义(χ2=15.298,P<0.01)。乙脑确诊病例共421例,发病率2012-2015年呈逐年下降趋势,2016年上升。不同年份乙脑发病率差异有统计学意义(χ2=24.791,P<0.01)。确诊病例在8月达到高峰,共269例(占63.90%);年龄以1~10岁为主共336例(占79.81%),<1岁、11~15岁和>15岁病例均增加;地区分布范围逐渐减小,呈西北部向西南部转移趋势,未感染地区重新出现确诊病例。结论贵州省乙脑疫情小幅反弹,乙脑病毒自然循环传播呈活跃趋势,感染者年龄后移,地区分布发生改变。应进一步开展病原监测和抗体水平检测,加强重点地区和人群的查漏补种,控制乙脑暴发或流行。

Objectives To analyze the epidemiological characteristics of Japanese encephalitis（JE）in Guizhou Province from 2012-2016 and to provide basic data for prevention and control of JE. Methods IgM antibodies against JE were detected with an enzyme-linked immunosorbent assay（ELISA）in blood and cerebrospinal fluid from patients suspected of having JE in Guizhou Province from 2012 to 2016.Data were analyzed with the software Excel and PASW Statistics 18.Results Laboratories identified 1,317 suspected cases of JE in Guizhou Province from 2012-2016.The male to female ratio of patients was 2.3：1.One thousand two hundred and seventy-five patients with JE were≤the age of 15 and accounted for 96.81% of patients.In 2012,0.57% of patients（2/350）werethe age of 15.In 2013,1.93%（6/311）were that age.In 2014,2.78%（6/216）were that age.In 2015,4.43%（9/203）were that age.In 2016,8.02%（19/237）were that age.The percentage of patients the age of 15 differed significantly from 2012-2016（χ2=23.145,P〈0.01）.Specimens from patients suspected of having JE were divided into three combinations：serum,cerebrospinal fluid,and serum and cerebrospinal fluid.JE was identified in serum from 55.35% of patients,in cerebrospinal fluid from6.61%,and in serum and cerebrospinal fluid 38.04%.Detection of IgM antibodies differed significantly among the different combinations of specimens（χ2=15.298,P〈0.01）.There are 421 laboratory-confirmed cases of JE in Guizhou from2012-2016.The number of cases decreased each year from 2012-2015 but increased in 2016.The rate of detection of IgM antibodies differed significantly in different years（χ2=24.791,P〈0.01）.Two hundred and sixty-nine cases（63.90%）were confirmed in August,representing the highest number during the year.Three hundred and thirty-six confirmed cases（79.81%）involved children ages 1-10,and an increasing number of cases tended to involve infants1 year of age,children ages 11-15,and teenagers the age of 15.The geographical distribution of cases gradually decreased,shifting from the northwest to the southwest.Some confirmed cases were found in areas with no JE. Conclu-sion The number of cases of JE has rebounded slightly in Guizhou Province.The natural circulation and transmission of the JE virus has remained active,infected people tend to be older,and the regional distribution of cases has changed.Pathogens need to be monitored further and antibody levels need to be measured further and supplementary immunization needs to be enhanced in some areas and some populations to control outbreaks and the prevalence of JE.