Abstract: Abstract: Objective   To understand the status of newly discovered and reemerged Oncomelania hupensis in Guichi District, Chizhou City from 2016 to 2021 for evidence to formulate the plans for prevention and control of schistosomiasis. Methods   Snail monitoring was carried out in accordance with the Work Specifications for Schistosomiasis Elimination and Technical Specifications for Snail Investigation. Information on the existing snail environment, suspected snail breeding environment and historical snail environment in Guichi District was collected from 2016 to 2021, and the area, the number, live snail density, living frame occurrence rates of snails and regional characteristics of the newly and reemerging snail environments in Guichi District were analyzed. Results   From 2016 to 2021, the environmental areas of newly emerging snails in Guichi District were 71.61, 0, 0.52, 0, 13.00 and 180.56 hm², and the environmental areas of reemerging snails were 82.27, 12.67, 8.48, 5.12, 28.50 and 291.59 hm², respectively. The number of newly emerging snail environments was 12, 0, 2, 0, 2 and 24, and the number of reemerging snail environments was 29, 6, 25, 20, and 283, respectively, for the 6 years. Average living frame occurrence rate was 18.41%, 0, 21.58%, 0, 17.58% and 19.66% for the newly emerging snails, and 8.46%, 28.80%, 17.15%, 13.49%, 8.55% and 21.52%, respectively for the reemerging snails. The average living density was 0.42, 0, 2.62, 0, 0.97 and 0.91 snails /0.1 m² for the of newly emerging snail environments, and 0.70, 1.01, 1.10, 1.65, 0.68 and 1.43 snails /0.1 m², respectively for the reemerging snail environments. The newly emerging snail environments in Guichi District were primarily in the beach at the Yangtze River in Meilong Community, Jiangkou Community and Wusha Town, Qiupu River beach in Niutoushan Town and Yinhui Town. The reemerging snail environments were mainly in Qiupu River beach in Xinghua Village Community and Yinhui Town and Shengjinhu beach in Tangtian Town. Yangtze River, Qiupu River and Jiuhua River were the main water systems where the newly emerged snail environments were located. The river systems where the snail reappeared were mainly located were Qiupu River, Baiyang River and Shengjin Lake. Conclusion   In recent years, there has been different degree of snail diffusion in Guichi District every year. For the key areas where new or recurrent snails appear, targeted snail control measures should be taken in time to prevent the spread of snails and schistosomiasis. 

Key words: Schistosomiasis, Oncomelania hupensis, Newly discovered snails, Reemergence, Guichi District