ABSTRACT
@#Abstract: Objective To analyze the impact of the flood disaster on the distribution of Oncomelania snails in 2020 in Wuhu City, to provide scientific basis for formulating the "14th Five-Year Plan" for schistosomiasis control and precise prevention and control measures in Wuhu City. Methods Systematic sampling combined with environmental spot check was used to investigate the distribution of snails in the historical snail's environment, existing snail's environment and suspected snail's environment in Wuhu City. The collected snails were crushed and examined by microscope to understand the death and life of snails and the infection of Schistosoma japonicum, and the density of live snails and other indicators were counted. Results The historical area of snails was 14 475.24 hm2 in Wuhu City, and the existing area of snails was 4 588.72 hm2, including 4 210.32 hm2 for lake type and 378.40 hm2 for hill type snails. The average occurrence rate of live snails was 14.59%, and the average density of live snails was 0.50 snails/0.1 m2 in Wuhu City. There were 2 745 snail breeding environments, of which 491 were lake type and 2 254 are hill type, accounting for 17.89% and 82.11% respectively. The existing snail area was mainly distributed in the beaches and ditches, accounting for 92.51% and 6.29% of the existing snail area respectively. Some snails were distributed in ponds, paddy fields and other environments. Among all the historical snail habitats, the majority were class Ⅱ and class Ⅲ environments (which still have the basic conditions for snail breeding at present), with a total of 1 739 sites (blocks), accounting for 63.35% of the total environment. No schistosomiasis infected snails have been found, and the newly discovered and recovered snails cover an area of 268.21 hm2 in Wuhu City. Conclusions The distribution of snails is extensive in Wuhu City, and snails are mostly distributed in beaches, which are vulnerable to the impact of flood disasters. The spread of Oncomelania snails is found in 30 marshlands in 3 counties in this survey. It is necessary to continue to strengthen snail monitoring after disasters, and take class Ⅱ and class Ⅲ environments as key areas for snail monitoring, so as to find, identify and evaluate the risk of schistosomiasis transmission as soon as possible, to avoid or reduce the impact of flood disasters on the process of schistosomiasis control, and promote the process of schistosomiasis elimination.