广州管圆线虫中间宿主福寿螺感染检测方法的比较

Comparison of detection methods for the third larvae of Angiostrongylus cantonensis in Ampullaria gigas

目的比较3种检测广州管圆线虫第Ⅲ期幼虫的方法,并采用简单易行、检测效率高、速度快的检测手段对温州疫区进行疫源地分级,寻求用于疫源地流行病学调查的有效方法手段。方法应用直接沉渣镜检法、胃蛋白酶消化法、螺肺检法3种方法分别对从温州广州管圆线虫疫源地采集的福寿螺进行检查,比较3种方法检查福寿螺体内广州管圆线虫第Ⅲ期幼虫的效果。并根据检查效率最高的一种方法的检查结果对温州市区、苍南县、永嘉县进行疫源地分级。结果3种方法检查福寿螺广州管圆线虫第Ⅲ期幼虫阳性率分别为60.0%(51/85)、32.9%(23/70)和15.9%(11/69),差异有统计学意义(P<0.01)。温州地区疫源地分级显示苍南县为Ⅳ级,永嘉县为Ⅲ级,温州市区为Ⅰ级。结论检查螺内广州管圆线虫第Ⅲ期幼虫的方法较适合于疫源地流行病学调查和分析判断。直接沉渣镜检法检测速度适中,对幼虫活力影响小,适合于幼虫的分离和动物接种试验;胃蛋白酶消化法适合于幼虫的分离和筛选;肺检法适用于疫区的流行病学调查或定性筛选。

Objective To compare the effect of 3 detection methods of the third stage larvae of Angiostrongylus cantonensis in Ampullaria gigas, and analyze the degree of the epidemic foci using the best method and explore this method for epidemiology. Methods Microscopic examination for deposit of A. gigas, digested by Pepsin and detecting lung of A. gigas were used directly to detect the third stage larvae of A. cantonensis. Epidemic focus classification of Wenzhou City, Cangnan County and Yongjia Conuty was determined according to the results of the most efficient method. Results Positive rates of the3 methods were 60.0%（51/85）, 32.9%（23/70）, 15.9%（11/69） respectively. There was significant difference among the 3 methods significantly （P〈0.01）. The research of infectiosity rank in the epidemic loci of A. cantonensi5 showed that infectiosity rank of Cangnan County was IV, Yongjia county was Ⅲ , Wenzhou City was Ⅰ. Conclusion Detection methods for the third larvae of A. cantonensis are suit for epidemiological investigation and analysis in the epidemic foci of A. cantonensis. Directly examining is quicker and operated simply, and there is no effective on activity of the third larvae, which is suited for detecting a great number of samples and inoculating for mice. Digesting method can be used to isolate and screen the third larvae. Detection of lung is suitable for the research of infectiosity rank and screening the epidemic foci.