江苏省血吸虫病监测预警关键技术研究与集成示范II5%杀螺胺颗粒剂大现场示范灭螺效果

Integration and demonstration of key techniques in the surveillance and forecast of schistosomiasis in Jiangsu Province II Molluscicidal effect of 5% niclosamide ethanolamine granules in large-scale settings

目的通过现场试验获得5%杀螺胺颗粒剂现场应用的技术指标,为血吸虫感染高危环境应急处置提供钉螺控制新技术。方法在扬州市邗江区（小现场）和仪征市（大现场）各选择1个环境进行5%杀螺胺颗粒剂喷撒灭螺试验,比较不同剂量、不同时间和是否环境清障条件下的杀螺效果。结果小现场试验显示,30、40、50 g/m^25%杀螺胺颗粒剂喷撒1、3 d和7 d后,钉螺死亡率分别为54.55%、68.41%和73.45%,57.27%、68.59%和80.28%,63.49%、77.58%和85.55%;其中30 g/m^2与40 g/m^2剂量组在喷撒后1、3 d钉螺死亡率差异均无统计学意义（P均〉0.05）,喷撒后7 d钉螺死亡率差异有统计学意义（χ^2=4.549,P〈0.05）,40 g/m^2与50 g/m2剂量组喷撒后1、3 d和7 d钉螺死亡率差异均无统计学意义（P均〉0.05）。大现场试验显示,未清障和清障环境采用40 g/m^25%杀螺胺颗粒剂喷撒3、7 d和15 d后钉螺死亡率分别为85.29%、83.89%、83.41%和87.70%、91.02%、91.84%;清障组喷撒后3~15 d钉螺总体死亡率为90.02%,显著高于未清障组（84.28%）（χ^2=9.950,P〈0.05）;清障与未清障组喷撒15 d后活螺密度分别由19.90只/0.1 m^2和19.83只/0.1 m^2下降至0.60只/0.1 m^2和2.60只/0.1 m^2,分别下降了96.98%和86.89%。结论 5%杀螺胺颗粒剂现场喷撒灭螺适宜剂量为40g/m2,对环境中高于50 cm的植被清障将提高灭螺效果。

Objective To evaluate the field molluscicidal effect of 5% niclosamide ethanolamine granules,so as to provide a novel Oncomelania hupensis snail control approach for emergency treatment of high-risk settings. Methods Snail control tests with spraying of 5% niclosamide ethanolamine granules were conducted in two settings of 2 counties,and the dose-,time- and setting-specific field molluscicidal effects were tested. Results In the small-scale setting,spraying of 5% niclosamide ethanolamine granules at doses of 30,40 and 50 g/m^2 resulted in 54.55%,68.41% and 73.45% 1-day snail mortality,57.27%,68.59% and 80.28% 3-day snail mortality,and 63.49%,77.58% and 85.55% 7-day snail mortality,respectively,and no significant differences were detected in 1- and 3-day snail mortality caused by spraying of 5% niclosamide ethanolamine granules at doses of 30 and 40 g/m^2（all P〉0.05）,while significant difference was found in the 7-day snail mortality（ χ^2 = 4.549,P〈0.05）. In addition,spraying of 5% niclosamide ethanolamine granules at doses of 40 and 50 g/m2 resulted in comparable 1-,3- and 7-day snail mortality（all P〉0.05）. In the large-scale setting,spraying of 5% niclosamide ethanolamine granules at a dose of 40 g/m2 resulted in 85.29% and 87.70% 3-day snail mortality,83.89% and 91.02% 7-day snail mortality,and 83.41% and 91.84% 15-day snail mortality in the environment-cleaning group and non-cleaning group,respectively. The overall snail mortality was 90.02% in the environment-cleaning group 3 to 15 days after spraying,which was significantly higher than that（84.28%）in the non-cleaning group（ χ^2 = 9.950,P〈0.05）. After 15 days of spraying with 5% niclosamide ethanolamine granules at a dose of 40 g/m2,the densities of living snails reduced from 19.90 and 19.83 snails/0.1m^2 to 0.60 and 2.60 snails/0.1 m^2 in the environment-cleaning group and non-cleaning group,with 96.98% and 86.89% reductions,respectively. Conclusion The appropriate dose of 5% niclosamide ethanolamine granules is 40 g/m^2 for snail control in the field,and environment cleaning of vegetation with a height of more than 50 cm may improve the molluscicidal efficacy.