澧水下游河道变迁、堤垸挽筑与血吸虫病流行——以湖南省安乡县为中心

Lishui River Downstream Channel Changes, Embankments Constructions and Schistosomiasis Prevalence: A Case Study of Anxiang County, Hunan Provence

东晋、南朝以来,荆江分流多次南下干扰澧水水系,从而导致澧水下游河道的剧烈变动。尤其道光以降,虎渡、藕池、松滋纷纷河决南下,冲入今安乡境内,将澧水主泓迫往西南。安乡水患从此多发,堤垸也开始大批修筑。由于荆江来水含沙量巨大,每年洪水退后留下大量淤泥,不利于血吸虫病中间宿主钉螺的存活;此外,在堤垸修筑后少经溃垸的区域,长年开垦破坏了钉螺的生存环境,使得安乡县成为滨湖诸县市中血吸虫病爆发最迟、疫情最轻的区域。然而在一些反复溃垸的地区,每年钉螺随洪水进入垸内,疫情则十分严重。

Lishui River downstream channel had changed a lot due to distributary channels of Yangtze River turned to go southward and disturbed water system of Lishui River since Eastern Jin dynasty. Things went worse as distributary channels like Hudu, Ouchi, Songzi broke and went southward into Anxiang County, and forced Lishui River downstream channel went southwest, especially since 1820s. Embankments had been built up to protect fields from floods. There is a mass of suspended sediment left by Yangtze distributary channels which made conditions not favorable for snails’ survival. Further, long-term cultivation destroyed snails’ habitat as well in regions not often influenced by floods. All this made Anxiang County’s epidemic situation not as severe as other counties in Dongting Lake Region. However, epidemic situation was pretty severe in regions where embankments always were destroyed by floods as snails went into embankments with floods.