【作者】 李源培； 何忠； 何明祯； 姜杰； 李君祥； 周艺彪； 张志杰； 姜庆五；

【Author】 LI Yuan-pei,HE Zhong,HE Ming-zhen,JIANG Jie,LI Jun-xiang ZHOU Yi-biao~1,ZHANG Zhi-jie~1,JIANG Qing-wu~1.1.Department of Epidemiology,School of Public Health,Fudan University,Shanghai 200032,China;2.Station for Schistosomiasis Prevention of Junshan District,Yueyang 414005,china.

【机构】 复旦大学公共卫生学院流行病学教研室； 岳阳市君山区血防站；

【摘要】 目的探索湖沼地区水位变化对钉螺消长的影响及其规律,为钉螺的有效控制和预测提供指导依据。方法选择湖南省岳阳市长江村垸外的一块典型钉螺孳生地为现场,收集2001-2009年间的水位资料和螺情资料,包括平均水位、最高水位和最低水位及活螺密度和阳性螺密度等。描述水位指标和螺情指标的时间分布情况,用广义相加模型(GAM)拟合分析水位变化与钉螺消长之间的关系。结果当年的平均水位和现场水淹天数对活螺密度的影响均有统计学意义,表现为二次曲线关系;当年的平均水位和上一年的现场水淹天数对阳性螺密度的影响均有统计学意义,表现为三次及更复杂分段样曲线关系。结论水位的高低和水淹天数的长短直接影响着钉螺的消长。水位变化对钉螺消长的影响主要表现为非线性的光滑函数关系。水淹天数对阳性螺密度的影响存在滞后效应。可以认为,平均水位在24.0m,水淹天数为3个月时,活螺密度保持较高水平。用GAM拟合水位变化对钉螺消长的影响可能更贴近实际而便于解释,也更容易发现两者之间的潜在关系和规律。更多还原

【Abstract】 Objective To explore the impact and its regularity of the changing water level on variance of snail population,so as to provide information for the effective controlling and prediction of snails.Methods A typical snail habitats closed to Changjiang County in Yueyang City,Hunan Province was selected as the survey field.The data on water level and snail change during 2001-2009 including the average water level,maximum water level,minimum water level,snail density and infected snail density were collected.The distribution of water level and snail indexes were described,a general additive model for the relationships between these indexes were also fitted.Results The impact of the average water level and the survey field watered out days in current year on the snail density was statistically significant,which showed a quadratic curve association.The impact of the average water level in current year and the field watered out days in past year on the infected snail density was also statistically significant,which showed a cubic curve or even a more complicated piecewise curve association.Conclusions The water level and the field watered out days affected the development of snail population directly.The changing water level had an impact on snail population change,which mainly presented as nonlinear smooth function relation.The impact of the field watered out days on the infected snail density showed a hysteresis effect.The snail density was predicted to retain a high level when the water level was 24.0m and the field watered out days was 3 months.It had obvious advantages to fit the relationship of the changing water level and the snail indexes with a general additive model which could get closer to reality and easier to find and explain the potential associations and regulations.更多还原