Kato-Katz法2送6检结合粪孵法用于血吸虫病现场筛查

Evaluation of Kato-Katz technique combined with stool hatching test in diagnosis of schistosomiasis japonica

目的探讨敏感性、准确性较高的血吸虫病病原学检查新方法。方法以血吸虫病流行区湖北省武汉市汉南区捞子湖村居民为对象,连续2d每天收集1次新鲜粪便样本,并采用加藤厚涂片法(Kato-Katz法)顺序制作6张涂片,检测粪便中血吸虫卵(2送6检);对检测阴性者再采用尼龙绢集卵孵化法对粪便样本复检,进行阳性检出率和克粪虫卵数(EPG)值的比较。同时收集相关的流行病学基础资料。结果 Kato-Katz法共检测562人,阳性67例;对Kato-Katz法检测阴性的495人进行粪孵法复检,阳性6例;两法检出总阳性者73例。以阳性病人73例计算,Kato-Katz法1送3检累计阳性为48例,累计阳性率为65.8%,漏检率为34.25%,2送6检累计阳性为67例,累计阳性率为91.8%,漏检率为8.22%,随着检测次数的增加,阳性检出率逐渐升高。6次累计阳性率比单次平均阳性率提高53.50%。病人EPG几何均数1～6片分别为61.12、31.92、23.71、20.88、19.35和18.83,显示涂片数较少时病人EPG偏高,病人EPG的准确性随涂片数增加而提高。结论为获得较高的血吸虫病检出率和准确的人群感染度,Kato-Katz法2送6检结合粪孵法值得应用。

Objective To develop an aetiology detection method with higher sensitivity and accuracy for schistosomiasis japonica. Methods The fresh fecal samples were collected from residents of a schistosomiasis japonica endemic village in Laozi County of Hubei Province. Two samples per person were collected in two consecutive days. Each sample was examined three times with Kato-Katz technique, then the negative cases were re-examined by the stool hatching test after the egg concentration with nylon-tissue bags. The detective rates and the relation with egg per gram （EPG） of different methods were analyzed and compared. The epidemiology data were collected as well. Results A total of 562 residents were examined by Kato-Katz technique, and 67 of them were positive. The samples of 495 negative persons were re-examined by using the hatching test after the egg concentration with nylon-tissue bags. Six persons were positive. The total number of positive cases was 73. The rates of Kato-Katz technique with three slides of one sample and six slides of two samples were 65.8% and 91.8%, respectively. The detective rate was increased with the increase of examining slides. The geometrical averages of EPG from one slide to six slides were 61.12, 31.92, 23.71, 20.88, 19.35 and 8.83,respectively. The accuracy of EPG increased with the increase of numbers of slides. Conclusion Kato-Katz technique with six slides of two samples is applicable in diagnosis of schistosomiasis japonica in order to achieve higher detective rate and more accurate EPG.