Kloos H, Gardiner C H, Selim A, Higashi G I
Am J Trop Med Hyg. 1982 Jan;31(1):122-7. doi: 10.4269/ajtmh.1982.31.122.
The use of cercariometry in epidemiological studies has been limited by turbidity, difficulty of recovering cercariae at low concentrations in natural waters, and by complex apparatus that requires a power source. The technique of differential filtration developed by Theron has been modified and tested in the laboratory and in the field in Upper Egypt for detection of Schistosoma haematobium cercariae. A recovery filter with a pore size of 30 micrometer was found to give the best results. The recovery rate in the laboratory was 51% on filtration of 5-liter samples of formalin-treated water, and 19-30% with 10- and 20-liter samples. This moderate efficiency is offset by simplicity of the technique, rapid filtration, and ease of reading the recovery filter, permitting sampling of large volumes of water in the field by persons with little training. Average densities of 0.024 cercariae per liter of water were found at the Nile and 0.029 cercariae per liter in the irrigation canals. Most cercariae were recovered between 0.700 and 0900 hours.
在流行病学研究中，尾蚴测量法的应用受到了限制，原因包括水体浑浊、在天然水体中低浓度时难以回收尾蚴，以及需要电源的复杂仪器。由塞伦开发的差异过滤技术已经在上埃及的实验室和实地进行了改进和测试，用于检测埃及血吸虫尾蚴。发现孔径为30微米的回收过滤器效果最佳。在实验室中，对5升经福尔马林处理的水样进行过滤时，回收率为51%；对10升和20升的水样，回收率为19%至30%。该技术的简单性、快速过滤以及易于读取回收过滤器的特点弥补了这种中等效率的不足，使得几乎没有经过培训的人员也能够在实地对大量水体进行采样。在尼罗河发现每升水的平均尾蚴密度为0.024个，在灌溉渠道中为每升0.029个。大多数尾蚴是在07:00至09:00之间回收的。
