吡螺脲硫酸盐可湿性粉剂在山丘型血吸虫病流行区的灭螺效果

目的　评价25%吡螺脲硫酸盐可湿性粉剂（WPPS）在山丘型血吸虫病流行区灭螺效果及其对鱼类的毒性。方法　2020年10月选取云南省南涧县一处有螺环境进行除障并划分为若干单元，计算钉螺自然死亡率。将25% WPPS配置成浓度为1、2 g/L的药液，将25%杀螺胺乙醇铵盐（WPNES）溶于水配置成浓度为2 g/L的药液，将不同浓度的药物均匀喷洒, 以等量清水作为空白对照。在施药后1、3、7 d，通过系统抽样法进行钉螺调查，观察钉螺死活。在南涧县选择一处鱼塘，将2 kg 25% WPPS（药物有效浓度20 g/L）均匀投撒于液面使其自然分散溶解，于投撒后8、24、48、72 h观察鱼类死亡情况。结果　施药1 d后， 1、2 g/L WPPS组钉螺校正死亡率均为97.99%，高于2 g/L WPNES组的94.11%（χ2] = 3.509、3.509，P均> 0.05）。施药3 d后，1、2 g/L WPPS组和2 g/L WPNES组钉螺校正死亡率均为100%。施药7 d后，1 g/L WPPS处理组钉螺校正死亡率为91.75%，2 g/LWPPS处理组钉螺校正死亡率为86.57%，均显著高于2 g/L WPNES处理组的57.76%（χ2] = 14.893、42.284，P均< 0.05）。鱼毒试验结果显示，2 kg 25% WPPS施药72 h后鱼类累计死亡率为0.67%。结论　WPPS可有效杀灭钉螺且对鱼类生物安全性较高，可应用于山丘型血吸虫病流行区灭螺。

Molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate in hilly schistosomiasis?endemic regions

Objective　To evaluate the molluscicidal effect of 25% wettable powder of pyriclobenzuron sulphate (WPPS) against Oncomelania snails in hilly schistosomiasis?endemic regions and test its toxicity to fish. Methods　In October 2020, a snail?infested setting which had been cleared was selected in Nanjian County, Yunnan Province and divided into several blocks, and the natural snail mortality was estimated. 25% WPPS was prepared into solutions at concentrations of 1 and 2 g/L, and 25% wettable powder of niclosamide ethanolamine salt (WPNES) was prepared into solutions at a concentration of 2 g/L. The different concentrations of drugs were sprayed evenly, and the same amount of water was used as blank control. Snails were surveyed using the systematic sampling method 1, 3 and 7 days post?treatment, and snail survival was observed. A fish pond was selected in Nanjian County, and 2 kg 25% WPPS was evenly sprayed on the water surface to allow the effective concentration of 20 g/L. Fish mortality was estimated 8, 24, 48 and 72 h post?treatment. Results　One?day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 97.99%, 97.99% and 94.11% adjusted snail mortality rates (χ2] = 3.509 and 3.509, both P values > 0.05）, and the adjusted snail mortality was all 100% 3 d post?treatment with 1 and 2 g/L WPPS and 2 g/L WPNES, while 7?day treatment with 1 and 2 g/L WPPS and 2 g/L WPNES resulted in 91.75%, 86.57% and 57.76% adjusted snail mortality rates （χ2] = 14.893 and 42.284, both P values < 0.05）. Treatment with 2 g/L WPPS for 72 h resulted in a 0.67% cumulative mortality rate of fish. Conclusion　25% WPPS is effective for snail control and highly safe for fish, which is feasible for use in hilly schistosomiasis?endemic regions.