现场诊断日本血吸虫感染常用方法比较

Comparison of Common Methods in the Field Diagnosis of Schistosoma Japonicum Infection

目的 比较三种常用诊断日本血吸虫感染的方法 ,在日本血吸虫病流行区进行现场诊断时的特性。方法 在湖北省和江西省各选取一个村庄为研究对象 ,各试点每位居民均接受改良加藤法、间凝法和孵化法检测感染 ,湖北试点只收集一次新鲜粪便标本制作 2张加藤涂片 ,江西试点收集连续 7d的新鲜粪便标本 ,每天制涂片 2张。同时收集相关的流行病学基础资料。结果 在两个试点中 ,各年龄组和性别的各种检测方法的阳性率变化趋势相同 ;间凝法和孵化法的检出率随着感染率的增加而上升。江西试点间凝法的敏感度和特异度分别为80 %和 48% ,单次加藤法和孵化法的敏感度分别为 6 8%和 33 % ;而湖北试点的孵化法阳性率却高于单次加藤法。结论 加藤法为现场诊断首选 ;孵化法易受现场条件限制 ,稳定性较差 ;间凝法假阳性率较高 。

Objective Comparing the performances of the three diagnostic techniques in the most important endemic areas for schistosomiasis japonica in China.Methods The Kato Katz technique, hatching test and indirect hemagglutination assay (IHA) were used to detect schistosoma japonicum infection in two villages, Zhonjiang and Zhuxi, which were selected from Hubei Province and Jiangxi Province, respectively. Single Kato examination was conducted in Zhonjiang Village, 7 repeated Kato examinations were conducted in Zhuxi Village. Basis epidemiologic data were collected in the same time.Results In both village, the trends of prevalences with age and sex were the same with the different methods and the proportion of positives detected by IHA and hatching increased with intensity of infection. The results of 7 repeated Kato examinations and hatching were used as gold standard (Zhuxi). Using this gold standard in Zhuxi, the sensitivity of IHA was 80% and its specificity 48%. The sensitivity of a single Kato measurement was 68% and of hatching 33%. In Zhonjiang, however, proportions of positives were considerably higher for hatching than for a single Kato examination.Conclusion The Kato Katz technique is recommended as the method of choice for the field diagnosis of schistosoma japonicum infection. Hatching is much more tedious, provides inconsistent and only qualitative results, and is not more sensitive than a single Kato. IHA is more sensitive but it results in many false positive cases and is therefore only suitable as an auxiliary method.