洞庭湖区溃垸前后血吸虫病流行区螺情变化分析

目的：了解洪涝灾害对血吸虫病流行区螺情的影响程度。方法：选择遭受过严重洪涝灾害且溃垸的8个围烷，回顾性调查围垸受灾前后螺情及螺等情况。结果：8个被调查溃垸中，除2个围垸垸内受灾后未发现钉螺外，其他6个垸垸内受灾后钉螺面积均有不同程度的扩大，钉螺总面积是受灾前的10．8倍。其中围堤湖垸受灾前垸内无螺。灾后发现了钉螺。受灾后垸内活螺平均密度，垸外阳性螺平均密度和钉螺阳性率在大部分溃垸比受灾前均有不同程度的降低。结论：洪涝灾害能引起大部分溃垸垸内钉螺不同程度的扩散以及能降低部分溃决提垸垸外的阳性螺平均密度和钉螺阳性率，钉螺是否扩散及其扩散程度受诸如决口处是有钉螺分布，活螺密度，水淹面积，泥沙覆盖面积等因素的影响。

Analysis on the Changes of Snail Status of Schistosomiasis Before and After Embankment Collapsed in Dongting Lake Region

Objectives To know the affecting degree of snail status by the flood in schistosomiasis epdemic areas.Methods The eight embankments suffered from disasterous floods and collapsed were selected in Dongting Lake; the changes of snail states and snail-killed etc.Before and after disasterous floods were surveyed by retrospectively. Results In the eight embankments, the snail areas inside embankment increased at different degree except two embankments where snail was not found after disaster, it was 10.8 times of that before disaster; Furthermore, after disaster the snail was found in the embankment enclosing village areas inside where it was not found before disaster; in most of embankments collapsed, the mean density of living snail inside embankment and mean density of infected snail and positive rates of snail outside embankment descended at different degree after disaster. Conclusions Inside embankment, the disastrous floods could lead to snails speading in most of embankments collapsed. Otherwise, outside embankment the flood led to reduce the mean density of infected snail and positive rates of snail in most of embankments collapsed, and the degree of snails spreading was affected by the factors such as the snail states at the collapsed place, mean density of living snail,immersed area by water, mud and sand ect.