山丘型血吸虫病流行区钉螺分布的动态分析

目的探索山丘型血吸虫病流行区钉螺分布的规律并求证其分布的动态性。方法在四川省普格县对钉螺分布进行1年的动态观察。随机设框,检获框内全部钉螺,经压碎法鉴定死活后,计数每框的钉螺数。采用均数、方差等统计指标描述钉螺的分布特征,并拟合负二项分布、对数正态分布和指数分布。结果2008年4、5、7、8、9、11月的钉螺分布服从负二项分布;6、10、12月及2009年2月的数据与选取的分布类型均不能有效拟合。结论普格地区的钉螺分布并非简单的负二项分布,可能是动态变化的过程并且可能存在分布不确定性。

Dynamic analysis of distribution of Oncomelania hupensis in mountainous regions

Objective To study the distribution of Oncomelania hupensis snails in mountainous regions and the dynamic charaeteristics of the distribution.Methods An environment called"Lanbao"closed to Puge County.Sichuan Provinee WaS selected as the study field.Random sampling was designed to determine the investigation sites.The snails were collected and the hying snaila were identified by the method of dissection in the laboratory.The distribution of snails was analyzed by some statistical indices,such as mean,variance and so on.Then the negative binomial distribution.log-normal distribution and exponential distribution were fitted to the snail data by the method of maximum likelihood estimation to explore the snail distribution in different time.Results The negative binomial distribution was fitted well to the snail data in April,May,July,August,September,November in 2008,and no distribution was fined to the snail data in June,October.December in 2008 and February in 2009.Conclusions The distribution of Oncomelania hupensis in mountainous regions is not simple negative binomial distribution,but pwbably a dynamic process and an uncertain distribution.