安徽省钉螺孳生环境分布时空分析

目的了解安徽省血吸虫病流行区钉螺及感染性钉螺时空分布特征。方法根据2016年安徽省钉螺调查建立的数据库,描述全省钉螺及感染性钉螺分布和变化趋势,分析有螺环境中钉螺空间分布和感染性钉螺在1950-2016年聚集分布情况。结果1950-2016年,安徽省共发现钉螺孳生环境22757个,其中曾为感染性钉螺环境5004个,分别呈单峰和双峰状变化,1970年是变化拐点;历史累计有螺面积共14.10万hm^2,其中88.08%于1950-1979年首次发现;共消灭11.45万hm^2有螺面积,77.17%的历史有螺环境在1970-1999年消灭。截至2016年,全省现有螺环境4830个,其中曾为感染性钉螺环境1051个;78.12%的现有螺环境已存在40年以上,65.75%的感染性钉螺环境在10年内消除了感染性钉螺。安徽省现有螺环境活螺密度存在空间自相关(Moran’s I=0.196,Z=139.63,P<0.001);局部热点分析显示有螺环境活螺密度在空间上呈聚集性,长江以南呈高值聚集,长江以北呈低值聚集;21个具有统计学意义的活螺密度高值聚集区分布于长江沿线及支流水系。时空扫描分析发现现有螺环境中感染性钉螺在4处区域存在时空聚集性。结论安徽省现有螺环境存在时间长久,仅靠药物难以消灭,必须结合环改灭螺。现有螺环境的活螺密度存在空间聚集性,部分聚集区也是近年的高风险区域。时空扫描分析发现的历史上感染性钉螺聚集分布的区域中,部分环境流行因素和人畜感染的风险仍然存在,还需将其作为重点防控区域。

Spatiotemporal distribution of Oncomelania hupensis snail habitats in Anhui Province

Objective To investigate the spatiotemporal distribution of Oncomelania hupensis snails and infected snails in the endemic areas of schistosomiasis in Anhui Province.Methods Based on the snail survey data in Anhui Province in 2016,the distribution of snails and infected snails were analyzed,and the spatial distribution of snails and spatial cluster patterns of infected snails were investigated in snail habitats in Anhui Province from 1950 to 2016.Results A total of 22757 snail habitats and5004 infected snail habitats were identified in Anhui Province from 1950 to 2016,which appeared single-peak and double-peak patterns,with an inflection point seen in 1970.There were 141000 hm^2 historically accumulative snail habitats,88.08%of which were firstly identified from 1950 to 1979,and totally 114500 hm2 snail habitats were eradicated,77.17%of whieh were eradicated from 1970 to 1999.There were 4830 snail habitats identified until 2016,in which 1051 were once detected with infected snails.In addition,78.12%of current snail habitats had been present for over 40 years,and infected snails had been eliminated in 65.75%of the infected snail habitats within 10 years.There was a spatial autocorrelation of the living snail density in current snail habitats in Anhui Province(Moran’s I=0.196,Z=139.63,P<0.001),and local hotspot analysis showed spatial clusters of living snails density in snail habitats,with high-value clusters in south of the Yangtze River and low-value clusters in north of the Yangtze River.The 21 high-value clusters of living snail density with statistical significance were distributed along the Yangtze River basin and its branches.Spatiotemporal scan analysis revealed spatiotemporal clusters of infected snails in 4 current snail habitats.Conclusions The current snail habitats have been present for a long period of time,and snails are difficult to be eliminated by chemical treatment alone,which requires the combination of environment improvements.There are spatial clusters of living snail density in current snail habitats in Anhui Province.The epidemic factors and risk of human and animal infections still remain in some clusters of historical infected snail habitats revealed by spatiotemporal scan analysis,which should be considered as the key target areas for snail control in Anhui Province.