湖沼地区行政村尺度的洲滩阳性钉螺空间分布特征及变化趋势

Study on spatial-temporal variation of infected snail in bottomland areas after an integrated control strategy at village level in the marshland and lake regions based on geographic information system

目的分析2004--2010年湖南省安乡县洲滩阳性钉螺空间分布特征及变化趋势，了解以传染源控制为主的综合防治措施的效果。方法建立2004--2010年安乡县基于行政村的垸外查螺空间数据库，运用全局空间白相关（Moran’s，）、局部空间白相关（AnselinLocal Moran’s，）与空间扫描统计量法探索洲滩阳性钉螺空间分布特征及变化趋势。结果安乡县发现有感染性螺的洲滩由2004年的23处减少为2010年的10处，阳性螺框出现率也逐年降低，由2004年的4．32％。下降到2010年的0．12‰。全局空间自相关结果显示，总体研究区域上2004和2005年阳性螺框出现率存在空间自相关（Moran’s I=0．21，P〈0．10；Moran’s I=0．13，P〈0．10），其他年份不存在空间自相关，呈随机分布；局部自相关分析结果显示，随着时间的推移H—H模式的村呈减少趋势，2007、2008和2009年均出现了H—L相关模式的村，而2010年局部自相关分析，仅有1村有统计学意义，为H—L相关模式；空间扫描统计量法分析结果与局部自相关结果基本一致，聚集区域呈减少趋势，聚集半径也逐渐变小。结论安乡县以传染源控制为主的防治策略取得了良好的效果，洲滩阳性钉螺空间分布特征也随之发生了变化，应根据目前的分布特征调整防治策略和措施。

Objective To evaluate the effect of an integrated control strategy and to quantify the spatial-temporal variation of infected snails in the bottomland areas after the strategy was implemented. Methods Based on the geographic database of infected snail distribution at the village level during 2004-2010 in Anxiang county, Hunan province, spatial autocorrelation analysis and spatial scan statistics were applied to analyze the spatial-temporal characteristics on the distribution of infected snails. Results The number of embankments with infected snails in Anxiang county decreased from 23 in 2004 to 10 in 2010, while the rate of frame with infected snail in embankments decreased from 4.32%e in 2004 to 0.12%e in 2010. The spatial distribution of infected snails was nonrandom, only in 2004 and 2005 with Moran＇ s I= 0.21 （ P 〈 0.10 ） and Moran＇ s I= 0.13 （ P 〈 0.10） respectively. Data from the local spatial auto-correlation analysis showed that the number of villages with H-H types of auto-correlation model had been gradually decreasing. The results of SaTScan statistics appeared the same as from the local spatial auto-correlation analysis, showing that the number of areas with increased risk was decreasing. Conclusion The comprehensive measures with emphasis on infectious source control seemed effective for schistosomiasis control program. The current distribution characteristics provided us with evidence that the resource assignment could be more reasonably implemented so as to control schistosomiasis in a more effective way.