Schistosomiasis is closely related to natural environmental factors. The changes of environmental factors such as temperature hydrology vegetation soil etc. all impact the scope and extent of schistosomiasis transmission. Poyang Lake is the largest freshwater lake and one of the major endemic areas with schistosomiasis in China. With global warming the imple-mentation of the Three Gorges Dam operation and the Poyang Lake Ecological Economic Planning the natural environment in Poyang Lake area has been and will continue to change especially the water environment and climate environment which are more closely related to the schistosomiasis transmission. These changes to some extent have affected and will continue to affect the prevalence and transmission of schistosomiasis. This article reviews the relationship between the natural environment and its changes and schistosomiasis transmission in the Poyang Lake region.

GPS was used in the snail survey of Nuanhuping marshland in Poyang Lake region and its application value was discussed. The results suggest that GPS which can measure the marshland area and survey area at real-time and draw electronic maps of snail situation rapidly, could realize the electronic and image management of the data from snail survey and provide more accurate information to the department in charge of schistosomiasis control.

Objective To understand the dynamic of Oncomelania hupensis snail status in Duchang County at north shore of Poyang Lake so as to provide the evidence for formulating the strategy of schistosomiasis control. Methods The data about the snail status in Duchang County from 2005 to 2012 were collected and the change trend of the snail status was analyzed. Re?sults From 2005 to 2012 all the average density of living snails the occurrence rate of frames with living snails the density of infected snails and the area with infected snails showed a trend of sharp decline and stayed at a low level. Compared to 2005 the above 4 indexes in 2008 decreased by 70.06% 90.33% 79.48% and 37.88% respectively and those in 2012 decreased by 99.35% 98.98% 99.33% and 93.84% respectively. The infection rates of snails fluctuated between 0.06%and 0.53%which showed a trend of first decrease and then increase. The snail area maintained at the level of 2 052.5 hm2 since 2007. Con?clusions Most of the indexes of the snail status in Duchang County have decreased to the lowest level in history since 2012 but the snail area is stable and the infection rate of snails shows a fluctuation trend which suggests that the risks of schistosomia?sis transmission still exist and the snail control still should be strengthened.