洪涝灾害对长江下游血吸虫病传播的影响

目的了解洪涝灾害对长江下游血吸虫病传播的影响,为制定防治对策提供依据。方法长江洪灾后每年按常规方法进行沿江地区人、畜血吸虫病调查,同时对沿江洲滩钉螺消长情况和有关影响因素进行纵向观察。结果洪涝灾害后沿江地区人、畜血吸虫病检查阳性率分别维持在0.65%~1.71%和0.14%~10.62%;钉螺面积和感染性钉螺面积逐年增加,且后者随前者增加而增加,两者相关具有显著性(r=0.866,P=0.005);洪灾后2年感染螺框出现率、钉螺感染率、感染性钉螺密度均呈下降趋势,第3年开始恢复性上升,急性血吸虫病发病率与此三项指标的相关具有显著性(r1=0.836,P1=0.010;r2=0.773,P2=0.024;r3=0.893,P3=0.003)。调查资料显示距长江口愈近,洲滩淹水时间愈长,平均潮差愈大,钉螺分布愈少,江阴及其下游未发现钉螺。结论长江洪涝灾害可引起钉螺扩散、急性血吸虫感染增加,而这种影响在灾后逐渐显现,具有延迟性;加强洪灾前后的预防控制措施均可有效控制血吸虫病的传播。

Impact of floodwater on schistosomiasis transmission in area of lower reaches of Yangtze River

Objective To understand the impact of floodwater on schistosomiasis transmission in the area of lower reaches of the Yangtze River. Methods The residents and domestic animals were surveyed for schistosomiasis by the conventional technique in lower reaches of the Yangtze River every year. At the same time, the distribution of Oncomelania snails and the impact factors were investigated in the marshland along the Yangtze River. Results The positive rates of schistosomiasis were kept about 1% in the residents and domestic animals in the regions along the Yangtze River. The snail areas and the infected snail areas increased year after year. There was a correlation between the snail areas and the infected snail areas (r =0.866,P =0.005). The rate of frame of infected snails, infected snails rate and density of infected snails fell in two years after the floodwater, and then rose renewedly. There were correlations among the morbidity of acute schistosomiasis and the rate of frame of infected snails, infected snails rate and density of infected snails(r_1=0.836, P_1=0.010 ;r_2=0.773,P_2=0.024;r_3=0.893,P_3=0.003). The time of marshland submerged was increasing and the average difference of tide height was rising and the snail areas were reducing as the distance to the estuary of the Yangtze River was near and near. There were no snails in the lower reaches of Jiangyin along the Yangtze River. Conclusions The flood disaster could impel snailsCD8] to spread and the acute infection of schistosome to increase. The impact emerged gradually after the flood disaster. In order to control the impact of the flood disaster on schistosomiasis transmission, the prevention and control should be potentiated around the flood disaster.