Abstract:

Objective  To investigate the changes of Oncomelania hupensis snails in the marshlands at the middle reaches of Yangtze River along Junshan area, Hunan Province, after the Three Gorges Project being completed and fully functional. Methods  Longitudinal monitoring on the snail prevalence was performed in the four distinctive marshlands, and corresponding data were collected on the changes of water levels and silt contents at the middle and lower reaches of Yangtze River before and fully functional Three Gorges Project. Results  The marshlands with snail distribution and areas of marshlands were reduced by 74.77% and 72.56%, respectively, from 2003 to 2015. The density of live snails was decreased by 97.20% and infected snails were not found in 2015. Conclusion  The areas with snail prevalence and snail distribution as well as average density of living snails and infected snails tend to decline in general at the middle reaches along Junshan area of Hunan Province after the Three Gorges project becoming fully functional.

Key words: Three Gorges Project, Marshlands, Oncomelania hupensis, Schitosomiasis