Objective: To optimize and simplify the survey method of Oncomelania hupensis snail in marshland endemic region of schistosomiasis and increase the precision, efficiency and economy of the snail survey.
Methods: A quadrate experimental field was selected as the subject of 50 m×50 m size in Chayegang marshland near Henghu farm in the Poyang Lake region and a whole-covered method was adopted to survey the snails. The simple random sampling, systematic sampling and stratified random sampling methods were applied to calculate the minimum sample size, relative sampling error and absolute sampling error.
Results: The minimum sample sizes of the simple random sampling, systematic sampling and stratified random sampling methods were 300, 300 and 225, respectively. The relative sampling errors of three methods were all less than 15%. The absolute sampling errors were 0.221 7, 0.302 4 and 0.047 8, respectively.
Conclusions: The spatial stratified sampling with altitude as the stratum variable is an efficient approach of lower cost and higher precision for the snail survey.
[摘要]目的 优化、简化湖沼型血吸虫病流行区钉螺调查方法, 提高钉螺调查精度、效率和经济性。方法 基于鄱阳 湖区域恒湖农场茶叶港草洲1块50 m×50 m试验样地, 全覆盖查螺后再分别采用简单随机抽样、系统抽样与分层抽样等3 种方法进行钉螺调查, 计算最小需求样本量、抽样相对误差与抽样绝对误差。结果 本研究中简单随机抽样、系统抽样 与空间分层抽样等3种方法的最小需求样本量分别为300、300和225, 抽样相对误差均小于15%, 抽样绝对误差分别为 0.221 7, 0.302 4和0.047 8。结论 用高程作为分层依据进行空间分层抽样是钉螺实际调查中节省成本、提高精度的有 效途径。.
Keywords: Comparison study; Marshland endemic region; Oncomelania hupensis; Sampling method; Schistosomiasis; Spatial stratified sampling.