Sentinel Surveillance of Schistosomiasis—China,2021

Introduction:This report analyzes the national surveillance data for schistosomiasis in 2021 to understand the current status and provide evidence for further policy actions to promote elimination.This analysis is in line with the National Surveillance Plan of Schistosomiasis,which was revised in 2020 to adapt to the new stage of moving towards elimination.Methods:Data from the 2021 national surveillance of schistosomiasis in humans,livestock,and snails were collected from 13 provincial-level administrative divisions(PLADs)and analyzed using descriptive epidemiological methodology.The antibody-positive rate and area of newly discovered and re-emergent snail habitats were calculated.Results:In 2021,a total of 31,661 local residents and 101,558 transient population were screened for antibodies using indirect hemagglutination assay(IHA).Of those who tested positive,745 local residents and 438 transient population underwent further parasitological examination,with only one stool-positive result in the transient population.Additionally,12,966 livestock were examined using the miracidia hatching test,with no positives detected.The total area of newly discovered and re-emergent snail habitats was 957,702 m^(2) and 4,381,617 m^(2),respectively.No infected snails were found using the microscopic dissection method,but six pooled snail samples were reported as positive using the loopmediated isothermal amplification method for detecting specific sequences of Schistosoma.japonicum,in Anhui and Jiangxi Provinces.Conclusions:The prevalence of schistosomiasis among humans and livestock was found to be low,however,a potential transmission risk was identified in certain areas.To reduce the risk of transmission,a comprehensive control strategy should be continued and new techniques should be implemented in the surveillance and early warning system.