Abstract: Objective  To study the longitudinal change of data on Oncomelania hupensis surveillance in different marshlands and the impact of recent water level in Xingzi County, Jiangxi Province.  Methods  All information including water level of hydrometric station and the data of snails at the marshlands of Xiguanhu, Majiawan and Ximiaoqian was collected to explore the longitudinal change of snails and analyze the relationship between snail distribution and recent water level with Spearman rank correlation analysis.  Results  The highest proportion of frames with living snails and living snail densities at Majiawan and Ximiaoqian was 89.66% （442/493） in 2002 and 66.72% （872/1 307） in 2007, 8.33 in 2001 and 7.39 snails per frame in 2006, respectively, and the lowest was 13.26% （126/950） in 2010 and 4.60% （55/1 195） in 2005, 0.42 in 2010 and 0.22 snails per frame in 2002, respectively, and tended to decrease gradually after 2007. At Majiawan,  infected snails were found in 2005 and 2009, the density and proportion of infected snails were 0.0033 and 0.0025 snails per frame, 0.09% （3/3 306） and 0.22% （3/1 389）. Infected snails were found in Ximiaoqian in 2001, 2003, 2005 and 2009, the highest density and proportion of infected snails were 0.005 0 snails per frame and 0.88% （6/684） in 2005. Infected snails were found in Xiguanhu in 2002 and 2003 with a density and proportion of 0.002 9 and 0.002 7 snails per frame, 0.10% （1/974） and 0.32% （1/312）, respectively. The correlation analysis between proportion of frames with living snails and density at Xiguanhu with the average water level of the first and second month before snail survey showed statistical significance, the correlation coefficient was 0.76, 0.71, 0.82 and 0.78（P<0.05）, respectively. The correlation between proportion of frames with living snails and density at Majiawan showed no statistical significance with the average water level of recent three months before snail survey. The proportion of frames with living snails and density at Xiguanhu were negatively correlated with the average water level of the first and second month before snail survey, the correlation coefficient was -0.67, -0.75, -0.79 and -0.72（P<0.05）, respectively.  Conclusion  The change trend of snail indicators in different marshlands in the County and impact of water level in recent three months on snail population are both different, and the snail control strategy in marshlands should therefore be adjusted.

Key words: Schistosomiasis japonica, Oncomelania hupensis, Water level