Influence of the Three Gorges Dam on schistosomiasis control in the middle and lower reaches of the Yangtze River

This paper summarizes the factors affecting schistosomiasis transmission in the middle and lower reaches of the Yangtze River before and after the completion of the Three Gorges Dam and analyzes schistosomiasis prevalence trends to provide a basis for the application of the Three Gorges project methodologies in other areas. The Three Gorges Dam has demonstrated a positive effect on schistosomiasis control. Hubei, Hunan, Jiangxi, Anhui, and Jiangsu in the middle and lower reaches of the Yangtze River are currently regions with a high prevalence of schistosomiasis. These five provinces contained 97.62% of known snail areas and 93.66% of calculated schistosomiasis cases with 90.07% of counties (cities, districts) not yet meeting the criteria for schistosomiasis transmission interruption by the end of 2016. After the Three Gorges Dam was built, the prevalence of schistosomiasis in the middle and lower reaches of the Yangtze River decreased. By the end of 2016, the estimated number of cases decreased by 92.75% and the snail habitat areas decreased by 6.56% compared to 2004. No acute schistosomiasis cases have occurred for two consecutive years since 2015.