[Endemic situation of schistosomiasis in national surveillance sites of Zhejiang Province from 2015 to 2019].

Objective: To analyze the endemic situation of schistosomiasis in national surveillance sites of Zhejiang Province, so as to provide the scientific evidence for formulating the new schistosomiasis surveillance program and consolidating schistosomiasis elimination achievements.

Methods: A total of 54 to 55 national surveillance sites and 6 risk monitoring sites were assigned in historical endemic regions of Zhejiang Province from 2015 to 2019, where the infections in humans, livestock, snails and wild feces were monitored. All data pertaining to the surveillance results were descriptively analyzed.

Results: There were 34 530 person-time local residents receiving serological screening for infections in national surveillance sites of Zhejiang Province from 2015 to 2019, and the seroprevalance of infections were 0.29% to 0.68%; however, no egg-positives were detected. During the period from 2015 to 2019, there were 62 086 person-time mobile populations receiving serological screening for infections in national surveillance sites of Zhejiang Province, and the seroprevalance of infections were 0.32% to 0.56%; additionally, there were 27 egg-positives identified, including 3 imported cases with schistosomiasis haematobia and one case with acute schistosomiasis japonica, indicating that the adjusted prevalence of infections were 0.01% to 0.07% among mobile populations. A total of 829 livestock were examined for infections, with no positives detected. There were 10.55 hm and 2.89 hm snail habitats found in national surveillance sites and risk monitoring sites of Zhejiang Province during the 5-year period, respectively; however, no infections were identified in snails. Moreover, a total of 305 wild feces were tested for infections, and no egg-positives were identified.

Conclusions: The schistosomiasis elimination achievement have been consolidated in Zhejiang Province; however, the risk factors of re-emerging schistosomiasis have not been completely eliminated, such as residual snails and imported schistosomiasis cases. Further surveillance and control activities of snails and the source of infections should be reinforced.