[Investigation of snails in Anhui Province in 2016].

Objective: To investigate the status of snails in Anhui Province in 2016, so as to provide the evidence for formulating the 13th Five-Year Plans for Schistosomiasis Control.

Methods: In 2016, a snail survey was conducted in Anhui Province according to the , covering all snail habitats or historical snail habitats and suspected environments of snail breeding, and the results of the survey were analyzed.

Results: In 2016, 22 848 environments were surveyed, and no schistosome-infected snails were found. There were 17 927 historical snail habitats in whole province, among which, the environments without changes, changed partly and changed completely accounted for 71.2%, 19.3% and 9.5%, respectively. The area of historical snail habitats was 1.410 billion m. There were 4 830 environments with snail habitats covering an area of 0.265 billion m in 38 counties of 7 cities, including newly emerging area of 1 287.65 hm and reemerging area of 1 375.32 hm. The density of living snails was 0.392 0 snails/0.1 m, and the rate of frame with living snails was 12.93%. The type of marshland and lake regions, and the type of hilly and mountainous regions accounted for 22.4% and 77.6% of number of snail habitats, and accounted for 86.7% and 13.3% of areas of snail habitats, respectively. Among the different types of vegetation in snail habitats, grass was superior owe to accounting for 82.2% of the number of snail habitats, 57.3% of the area with snail habitats, and the highest density of living snails (0.413 9 snails/0.1 m). Among the different types of environments in snail habitats, the ditch was superior owe to accounting for 56.8% of the number of snail habitats, the highest density of living snails (0.570 3 snails/0.1m) and the highest rate of frame with living snails (18.57%), and the beach was superior owe to accounting for 87.8% of the area with snail habitats. In Anhui Province, the first year of snails and schistosome-infected snails being found was 1950 and 1952, respectively, and the latest year of schistosome-infected snails being found was 2012. The map showed that the most environments with snail habitats were distributed along the Yangtze River in Anhui Province.

Conclusions: For the first time, the investigation has built the database and map of snail spatial distribution, which truly reflect the historic and current status of snail distribution in Anhui Province and can provide the evidence for formulating the 13th Five-Year Plans for Schistosomiasis Control and improving the schistosomiasis prevention and control work in the future.