一种基于代表性样点的钉螺密度抽样调查设计方法

抽样设计是钉螺调查的关键环节，直接影响到统计推断的总体精度。目前湖沼型血吸虫病流行区钉螺调查常用的系统抽样设计方法存在样本量大、代表性不强、抽样效率不高等问题。通过对与钉螺空间分布上具有协同变化的环境因子进行模糊聚类分析，寻找可代表钉螺空间分布的代表性样点，提出一种基于代表性样点的抽样设计方法。将本研究设计的方法应用于鄱阳湖区恒湖农场茶叶港草洲的钉螺抽样设计研究，对采集的代表性样点进行误差分析，并将抽样结果与简单随机抽样和系统抽样方法进行精度比较。结果显示：本研究提出的“基于代表性样点的钉螺抽样设计方法（SORS）”明显优于简单随机抽样和系统抽样，抽样绝对误差分别为：0.440 7、1.551 4、3.565 3，相对误差分别为：1.048 1、3.689 7、8.479 6。本研究表明新方法能够获得比现有血防部门的钉螺调查方法更高的估算精度，可为优化湖沼型血吸虫病流行区钉螺调查方法提供借鉴。 关键词： 模糊聚类；抽样设计；代表性样点；钉螺

A Sampling Method Based on the Representative Sampling Sites for Estimating the Density of Oncomelania hupensis

Sampling site design plays a vital role in the survey of oncomelania hupensis,and directly affects the accuracy of statistical inference results.Currently,many problems,such as large samples demanded,poor representativeness and low efficiency in the traditional systematic sampling method in the marshland schistosomiasis epidemic area were met.This research proposed a spatial sampling method of oncomelania survey based on the representative samples-SORS,in which the Fuzzy c-means clustering analysis of snail environmental co-variation was performed to explore the spatial distribution characteristics This method was applied to snail survey in Chayegang marshland of Henghu farm in the Poyang Lake region,error analysis of the collected representative samples was conducted,and a comparison study was made among the outcomes of the SORS,the random sampling method and the traditional systematic sampling method.The results showed that the SORS method proposed was obviously better than the random sampling method and the traditional systematic sampling method,the absolute errors of snail number are 0.440 7,1.551 4 and 3.565 3,the relative errors of snail number are 1.048 1,3.689 7 and 8.479 6,respectively.It implies the new snail sampling method could obtain higher estimation accuracy than the current snail survey method,which could provide new scientific basis for optimization of snail survey method in the marshland schistosomiasis epidemic area in China.