Effect of integrated schistosomiasis control measures on Oncomelania snails in river channels connecting the Yangtze River in Nanjing City / 中国血吸虫病防治杂志

ObjectiveTo evaluate the effectiveness of Oncomelania snails control following the implementation of integrated schistosomiasis control measures in river channels connecting the Yangtze River in endemic areas of Nanjing City. MethodsThe river channels connecting the Yangtze River with snails in Nanjing City were selected as the study pilots. The integrated schistosomiasis control measures implemented in the study pilots were investigated by means of retrospective analyses and field surveys from 1998 to 2019, and the effectiveness of snail control was evaluated. Results Integrated control measures with emphases on environmental improvements including water resource projects for schistosomiasis control were implemented in the study pilots during the period from 1998 to 2019, including river bank concretion with 84.51 km in length, marshland cutting and dredging with 50.41 km in length, building 2 sluices and 3 overflow dams, digging one floodway and snail control with chemical treatment that covered an area of 3 370.80 hm2. No Schistosoma japonicum infection had been detected in snails since the completion of the integrated control measures. In addition, snails had been eliminated in 6 river channels connecting the Yangtze River until 2019, with the snail habitats reducing from 214.33 hm2 to 52.22 hm2 in 10 river channels connecting the Yangtze River and the snail density reducing to below 0.1 snails/0.1 m2 in snail-breeding river channels connecting the Yangtze River. Conclusions The integrated schistosomiasis control measures with emphases on environmental improvements may effectively control snail breeding and spread in rivers connecting the Yangtze River in endemic areas of schistosomiasis; however, the maintenance of the project and snail surveillance and control should be intensified following the completion of the integrated schistosomiasis control measures.

[Endemic situation of schistosomiasis at national surveillance sites in Nanjing City, 2015].

OBJECTIVE: To understand the dynamic endemic situation of schistosomiasis in Nanjing City, 2015, so as to provide evidences for policy-making of schistosomiasis control. METHODS: According to The National Scheme of Schistosomiasis Surveillance (2014), the endemic situation of schistosomiasis was monitored in 11 national surveillance sites in Nanjing. RESULTS: The positive rates of serological (IHA) and stool examinations were 2.97% (97/3 269) and 0 for local residents, and 0.52％ (12/2 298) and 0 for migrant people, respectively. No schistosome-infected livestock was found. Totally 147.295 3 hm2 area with Oncomelania hupensis snails were found, but no schistosome-infected snails were discovered. CONCLUSIONS: The endemic situation of schistosomiasis declines greatly in Nanjing City in 2015. However, the control work still should be strengthened to consolidate the achievements of schistosomiasis control.