[Impact of " Elaphurus davidianus return home project" on the transmission of schistosomiasis in Poyang Lake areas].

Objective: To investigate the prevalence of Schistosoma japonicum infections in Elaphurus davidianus released to Poyang Lake areas and evaluate the impact of the project of " E. davidianus released to wild environments for natural reproduction and growth" "( E. davidianus return home project") on the transmission of schistosomiasis in Poyang Lake areas.
Methods: During the period from April 2018 to December 2019, the population distribution, inhabiting activity and natural reproduction of E. davidianus released to Poyang Lake areas were investigated by means of GPS and artificial observations. The S. japonicum infection was identified in animal feces in E. davidianus inhabitats using a hatching test, and snail distribution was surveyed in E. davidianus inhabiting grass islands using a systematic sampling method.
Results: A total of 51 E. davidianus were released to the Poyang Lake areas in 2018, which subsequently produced 5 E. davidianus habitats in Yinlong Lake, Longkou, Nanchi Lake, Lianzi Lake and Zhu Lake. E. davidianus was found to predominantly inhibit in grass islands, farmlands and forest lands in hilly regions around the Poyang Lake areas. The natural reproduction rate of E. davidianus was 25% in the habitats in 2019, and the mean density of snails was 0.009 to 0.039 snails/0.1 m ² in E. davidianus inhabitats; however, no S. japonicum infection was identified in snails. In addition, the mean densities of wild E. davidianus and bovine feces were 4.6 samples/hm ² and 2.1 samples/hm ² , Conclusions The E. davidianus released to Poyang Lake areas may get infections with S. japonicum , and cause schistosomiasis transmission through fecal contamination in grass islands. The impact on and the prevalence of S. japonicum infection was 4.35% and 13.16% ( P = 0.236), respectively; however, the intensities of S. japonicum infections were "+++" and "+", respectively.
Conclusions: The E. davidianus released to Poyang Lake areas may get infections with S. japonicum , and cause schistosomiasis transmission through fecal contamination in grass islands. The impact on local schistosomiasis transmission and the response strategy requires to be investigated following the release of E. davidianus to lake regions, to ensure the achievement of the goal of schistosomiasis elimination and the successful implementation of the " E. davidianus return home project" in Poyang Lake areas.