高山峡谷型血吸虫病流行区钉螺的空间分布特征及灭螺方法的探讨

Spatial distribution and elimination of Schistosome japonicum intermediate hosts Oncomelania hupensis in mountainous regions

目的探讨高山峡谷型血吸虫病流行区钉螺的空间分布特征及灭螺方法。方法选取普格县特兹乡作为研究现场设框查螺；选择面积均为1000m^2、活螺密度分别为9．88只／0．11m^2和9．80只／0．11m^2的2块渗水草地作为灭螺现场；试验组用“堆敷”灭螺法，对照组用喷洒灭螺法，采用系统抽样方法（5m×5m）查螺比较2种方法的灭螺效果，样本量均为40框。结果钉螺主要分布在渗水草地、沟和田三类环境中，有螺面积以田中最多，但其活螺平均密度相对较低，其次是渗水草地且活螺平均密度较高；在灭螺前，试验组和对照组有螺框出现率分别为87．50％和82．50％。钉螺死亡率分别为3．89％和4．16％。在灭螺3个多月后，试验组没有发现活螺，而对照组有螺框出现率（77．50％）（χ^2=0．31，P〉0．05）和钉螺死亡率（7．03％）（χ^2=3．12，P〉0．05）均没有明显的降低，活螺平均密度下降幅度也不大，仅下降8．88％。结论“堆敷”灭螺法是一种比较有效的灭螺方法。

Objective To explore the spatial distribution and elimination of Oncomelania hupensis in mountainous regions. Methods Puge County in Tezi township was selected as the study site and the quadrates were placed randomly to investigate snail. The two sods with water were selected as the sites of snail elimination. One sod with area of 1000 m^2 and mean density of 9. 88 snails/0. 11 m^2 was selected as the trial group with ＇heaping＇ method, and the other with area of 1000 m^2 and mean density of 9. 80 snails/0. 11 m^2 as the control group with sprinkling method. The molluscacidal effect of the two methods was compared by systematic sampling（5 m ×5 m）. The sample size was 40 quadrates. Results The snail distributed mainly in the sods with water, canals and farmlands. Among the three snail habitats, the area with snail was the most in the farmlands with relatively lower density of living snail; the next was the sods with water, with relatively higher density of living snail. Before killing snails, the rate of quadrates with snails was 87.50% in the trial site, and 82. 50% in the control site. The mortality of snails was 3.89% in the trial site, and 4. 16% in the control site. After three months, no living snails were found in the trial site, while in the control site, the rate of quadrates with snails （χ^2 =0. 31, P 〉 0. 05 ）and the mortality of snails （χ^2 = 3.12, P〉0.05） did not decrease significantly, and the density of living snails only reduced by 8.88%. Conclusion The ‘heaping＇ method is an efficacious measure for snail control.