Surveillance on schistosomiasis in five PLADs of the People’s Republic of China in the post-elimination era

Abstract

Background: The People’s Republic of China (P. R. China) has made significant progress on schistosomiasis control. Among the 12 provinces (municipality, autonomous region) with schistosomiasis endemic in P. R. China, Guangdong, Shanghai, Fujian, Guangxi and Zhejiang provincial-level administrative divisions (PLADs, following as five PLADs) had successively eliminated schistosomiasis during 1985–1995. However, consolidation of the schistosomiasis elimination in these five PLADs remains challenging. In the current study, we sought to understand the epidemic situation in these post-elimination areas and their surveillance capabilities on schistosomiasis. Methods: Annual data reflecting the interventions and surveillance on human beings, cattle and snails based on county level from 2005 to 2016 were collected through the national schistosomiasis reporting system and the data were analyzed to understand the epidemic status of schistosomiasis in the five PLADs. Ten counties were selected according to the endemic situation before elimination in the five PLADs. A standardized score sheet was designed to assess the surveillance capacity for schistosomiasis of selected disease control agencies in five PLADs and ten counties. Assessment on surveillance capacity including schistosomiasis diagnostic skills, identification of snails’ living and infection status and knowledge about schistosomiasis and its control were made. And the accuracy rate of the assessment was calculated. Results: The comprehensive assessments showed that no local cases in humans and cattle or infected snail were found in these five PLADs since 2005, and the surveillance abilities on schistosomiasis of the prevention and control institutions in five PLADs were appropriate. However, from 2005 to 2016, a total of 221 imported cases were detected in Zhejiang, Shanghai and Fujian PLADs, and 11.98 hm2 of new snail habitats were found in Zhejiang, Shanghai and Guangxi PLADs. In addition, snail infestation reoccurred in 247.55 hm2 of former snail habitats since 2011. For the surveillance capacity assessment on diagnosis skills, the accuracy rate of IHA was 100%, and the accuracy rate of MHT was 89.3%. For snail identification, the accuracy rate of identifying the snails’ living status was 100%, and the average accuracy rate of identifying infection status of snails was 98.1%. The average accuracy rate of the questionnaire survey was 98.0%.Conclusions: Elimination of schistosomiasis was consolidated successfully in five PLADs of P.R. China due to effective and strong post-elimination surveillance. Comprehensive consolidation strategies should be focused on the elimination of residual snails and the prevention of imported infection sources among the five PLADs to consolidate the achievements of schistosomiasis control.