[Surveillance and risk assessment system of schistosomiasis epidemic focus in Hankou marshland of Wuhan City].

OBJECTIVE: To construct a monitoring and risk assessment system of schistosomiasis epidemic focus in marshland, so as to grasp the risk of schistosomiasis transmission, and to provide the technical support for targeted prevention and control measures. METHODS: The crowd and the risk source of schistosomiasis in Hankou marshland in Wuhan City were monitored to grasp the risk factors of schistosomiasis. The risk level was evaluated by the three-dimensional risk matrix and three-dimensional visualization method. RESULTS: The total numbers of people on holidays and working days were 59 582 and 36 382 persontimes a day respectively in Hankou marshland. Fishing and swimming were the most common ways to contact the river water. The most majority of the people exposed to river water were male (73.9%), retirees (36.1%), local residents (69.7%) and people whose income was 1000 - 3000 yuan per month (52.1%), and the awareness of protection of them was low. In spring, the average density of living Oncomelania hupensis snails was 0.993/0.1 m2, the rat density was 7.72%, and the density of wild feces was 0.78/hm2. In autumn, the average density of living snails was 0.596 /0.1 m2, the rat density was 5.22%, and the density of wild feces was 0.32/hm2. The average density of living snails, the rat density and the density of wild feces were reduced by 39.9%, 32.4% and 59.0% respectively in autumn compared with those in spring. The risk assessment results of three-dimensional matrix showed that part 1 and part 2 were medium risk, part 3 was high risk and part 4 was maximum risk. The risk assessment results of the visualization method showed that the risk level increased from part 1 to part 4, which were basically consistent with the results of the risk matrix. CONCLUSIONS: There is a relatively large risk of schistosome infection in Hankou marshland in 2013. The surveillance and risk assessment system of epidemic focus is feasible and scientific.

[Practice of engineering management and its effect on schistosomiasis control in Hankou marshland, Wuhan City].

OBJECTIVE: To investigate the Oncomelania hupensis snail control effect of schistosomiasis control engineering in marshland within Wuhan City. METHODS: The engineering measures including surface barrier removal, molluscicide, flatting surface, topsoil stripping, topsoil covering and ditch renovation were applied to transform Hankou marshland. Then the corresponding technical parameters of engineering measures were put forward. The situation of snails was analyzed before and after the transform project. RESULTS: The total length and area of the project were 6 015 m and 87.21 hm2, respectively, including 17.44 hm2 of topsoil landfill, 52.08 hm2 of topsoil covering and 23 new ditches. After the transformation, the average length of the new groove, the groove top width, groove depth, height difference, and the average values of slopes and ditch bottom slope were all increased, while the average values of the width and height of the ditch were decreased. At the same time, the marshland beach surface had a new slope that the embankment was higher than the river and no living O. hupensis snails were found then. CONCLUSIONS: The snail breeding environment in Hankou marshland has been effectively changed by the project. However, the constant monitoring and engineering management are still needed to consolidate the effect.