Schistosomiasis Surveillance - China, 2015-2018.

Background The prevalence of schistosomiasis in China is at the lowest level in history, and sentinel surveillance sites of schistosomiasis have fully covered all epidemic areas of China. This article has analyzed the surveillance data for the last four years and can help guide the next stage of surveillance work at the national level, including the scope of surveillance, surveillance content, and surveillance methods, etc. Methods Data from the National Schistosomiasis Surveillance System were collected. The infection rate of schistosomiasis among the human population, livestock, snails, and the change of the breeding area of snails in sentinel surveillance sites for four consecutive years were analyzed, and the trends in schistosomiasis prevalence in surveillance sites were determined. Results The prevalence of schistosomiasis in all sentinel surveillance sites of China showed downward trends from 2015 to 2018 with infection rates decreasing in this time period for local human population (0.05% to 0.00%), the floating population (0.020% to 0.003%), and cattle (0.037% to 0.000%). No infected snails were found during the period. From 2015 to 2018, the total area of newly found habitats of snails (Oncomelania hupensis, O. hupensis) were 34,730 m(2), 1,367,694 m(2), 18,944 m(2), and 50,420 m(2), and the total area of re-emergent habitats of snails (O. hupensis) were 822,194 m(2), 1,391,779 m(2), 1,516,292 m(2), and 1,750,558 m(2), respectively. Conclusions and Implications for Public Health Practice The prevalence of schistosomiasis in human and livestock is going down and is sustained at a very low level, but new and re-emerging habitats of O. hupensis are new challenges regardless of the achievement of schistosomiasis control. Therefore, two actions are necessary to effectively further reduce the transmission risk of schistosomiasis: 1) taking effective measures to control the source of infection of schistosomiasis; and 2) reducing the breeding areas of O. hupensis.