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目的研究氯硝柳胺杀灭钉螺的效果并了解影响其杀灭效果的主要因素。方法采用实验流行病学方法,对中国血吸虫病流行区的钉螺通过随机分层抽样,抽取了10个省(市)33个县共37个点,采集钉螺,随机分组,用不同浓度的氯硝柳胺分别浸泡24 h、48 h,观察其杀灭效果,计算不同药物浓度、不同作用时间和不同生境的LC50。统计分析采用SPSS 13.0软件进行。结果氯硝柳胺溶液1．0 mg／L浸泡24 h和0．5 mg／L浸泡48 h,杀螺率均达100％。同一作用时间,对钉螺的杀灭效果随着药物浓度降低显著下降,浸泡钉螺24 h,LC50均值为0．0939 mg／L,而浸泡钉螺48 h,LC50均值为0．0625 mg／L,浸泡24 h和48 h间的杀灭钉螺LC50差异有统计学意义(t=5．001,P<0．01)。在一定的浓度范围内,氯硝柳胺对钉螺的杀灭效果在48 h、不同生境(山丘型、湖沼型和水网型)Slg LC50之间的差异具有统计学意义(F=4．264,P<0．05)。非条件logistic回归分析,浓度、时间、生境的标准化回归系数估计值分别为2．047(OR=5．573)、0．263(OR=2．924)、0．187-0．210(1．969-2．560)。结论氯硝柳胺能有效杀灭钉螺,药物浓度、作用时间以及钉螺孳生地类型为其主要影响因素。
Objective To study the effects of niclosamide on snail killing and to understand the main factors affecting its killing effect. Methods Using experimental epidemiological methods, snails of endemic areas of schistosomiasis in China were randomly stratified and sampled. Totally 37 sites in 33 counties of 10 provinces (cities) were collected. Snails were collected and randomly divided into three groups: Dipyridamole was immersed for 24 h and 48 h, respectively. The killing effect was observed and the LC50 values of different drug concentration, different time and different habitats were calculated. Statistical analysis using SPSS 13.0 software. Results Niclosamide solution was immersed in 1.0 mg / L for 24 h and 0.5 mg / L for 48 h, the killing rate reached 100%. At the same time, the killing effect of Oncomelania snails decreased significantly with the decrease of drug concentration. Soaking snails for 24 h resulted in a mean LC50 of 0.0939 mg / L and soaking snails for 48 h, with an LC50 of 0.0625 mg / L, The LC50 of killing snails in 24 h and 48 h was statistically significant (t = 5.001, P <0.01). In a certain range of concentration, the killing effect of niclosamide on snails was at 48 h. The difference of Slg LC50 in different habitats (hill type, lakeside type and water network type) was statistically significant (F = 4. 264, P <0.05). The unconditional logistic regression analysis showed that the estimated standardized regression coefficients of concentration, time and habitat were 2.047 (OR = 5.573), 0.263 (OR = 2.924), 0.187-0.210 .969-2.560). Conclusion Niclosamide can effectively kill Oncomelania snails, its concentration, duration of action and types of snail breeding sites are the main influencing factors.