氯硝柳胺杀灭钉螺效果影响因素分析

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24h、48h，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1．0mg／L浸泡24h和0．5mg／L浸泡48h，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24h，LC50均值为0．0939mg／L，而浸泡钉螺48h，LC50均值为0．0625mg／L，浸泡24h和48h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48h、不同生境（山丘型、湖沼型和水网型）SlgLG50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。

A study on the effect of Oncomelania hupensis hupensiss killed with niclosamide in China

Objective To study the effect of Oncomelania hupensis hupensis of niclosamide, and exploring the main influencing factors. Methods The samples of Oncomelania hupensis hupensis were collected from 37 sampling sites in 33 counties of 10 provinces by means of stratified random sampling methods in accordance with the categories of Oncomelania hupensis hupensis habitats. Samples were randomly located into study group and control group. Oncomelania hupensis hupensis of the study group was marinated in different concentration liquor of niclosamide which was confected with water for 24 hours or 48 hours, then LC50 of niclosamide by which Oncomelania hupensis hupensis was killed and amount calculated. The influencing factors of the mortality of Oncomelania hupensis hupensis in the study group was statistically analyzed by X2 test and by multiple logistic regression using SPSS 13.0 statistical software. Results The mortality of Oncomelania hupensis hupensis of the two test groups which were marinated in 0.5 mg/L liquor for 48 hours and 1.0 mg/L liquor for 24 hours was 100% . The effect of Oncomelania hupensis hupensis killed by niclosamide was markedly reduced along with the reduction of drug concentration. The average LC50 rates of niclosamide liquor by which Oncomelania hupensis hupensis killed for the 24 hours and 48 hours in the study group, were 0.0939 mg/L and 0.0625 mg/L, respectively. There was significant difference between the two test groups (X2=5.001,P<0.01). In determinate range of concentration, the mortality of Oncomelania hupensis hupensis showed significant difference among the geographic types of habitat (X2 = 4.264, P < 0. 05 ) . By means of multiple logistic regression using SPSS 13.0 statistical software, the estimate value of coefficient of regression on the influence factors, drug concentration, test time and the geographic types of habitat were 2. 047 ( OR = 5. 573), 0.263 ( OR = 2.924) and 0.187- 0.210 ( OR = 1.969-2.560), respectively. Conclusion Niclosamide could kill Oncomelania hupensis hupensis effectively. The main influencing factors on the efficacy of niclosamide by which Oncomelania hupensis hupensis was killed, appeared to be drug concentration, time of testing and the geographic types of habitat.