The Specifications Research And Effect Analysis Of Engineering Modification And Maintenance For Schistosomiasis Control In Marshland

Objective:Researching and developing the technical standards of engineering modification and engineering maintenance for schistosomiasis control in marshland,and carrying out the practice of engineering in Hankou marshland to verify its molluscicidal effect.Methods:Through literature analysis,expert consultation method and engineering practice to research and develop technical standards of engineering modification and engineering maintenance for schistosomiasis control.The supervision company carried out geographical mapping,quality control and construction evaluation for the project implementation process.Through the method of information-based snail survey,snail survey was conducted before and after engineering modification and engineering maintenance in Hankou marshland.Oncomelania snails captured in snail survey were identified by the method of crawling and knocking and escaping cercariae to identify the death and infection of schistosomiasis.Using of Google Earth combined with GPS data to set up the Hankou marshland snail digital database.50%niclosamide wettable powders as molluscicide was used in the process of engineering modification,the dose was 2g/m2.The database of the snails,engineering and geo mapping were collected and established by Excel 2016.The data were statistically analyzed by SPSS 20.0 software,and the test level was a=0.05.Results:Based the geological environment of Hankou marshland,the results of the technical standards of engineering modification and engineering maintenance for schistosomiasis control and the construction process in turn is surface removal,topsoil stripping and covering,beach surface leveling,filling the old and opening new,building isolation belt,vertical warning signs and billboards,which combines snail survey and drug snail control.A detailed project implementation index and its technical parameters are formulated,which mainly including:Top width of ditches(5.1m),Bottom width of ditches(1.5m),Depth of ditches(1.5m),Ratio of slope(1:1.5-1:1.2),Ditch slope(?0.5%),Beach slope(?0.5%),Beach compacted density(?0.8),Beach Planeness(?80mm),Topsoil striping(20cm),topsoil covering(30cm),and Beach spacing(100m).The evaluation of the construction results of the engineering modification showed that bottom width of ditches,depth of ditches,ratio of slope,ditch slope and beach slope of Hankou marshland were 1.6 ± 0.4m,1.6 ± 0.6m,0.8±0.4,1.1±0.5%and 1.7±0.8%respectively,which reached the design standards according to statistical test.Topsoil stripping,topsoil covering and Beach spacing through construction monitoring meets design requirements.The evaluation of the construction results of the engineering maintenance showed that bottom width of ditches,depth of ditches,ratio of slope,ditch slope,beach slope,beach compacted density and beach Planeness of Hankou marshland were 1.7±0.6m,1.3±0.4m,0.7±0.3,1.0±0.3%,1.0±0.5%,0.6±0.land 25.8± 1.8mm respectively,which reached the design standards excepted depth of ditches and beach compacted density according to statistical test.Topsoil tillage depth through construction monitoring meets design requirements.The ditch section was still met the maximum flow requirements of Hankou marshland,but the beach compacted density was low,which do not met the requirements of the project.After engineering modification and engineering maintenance,the density of Oncomelania Snail decreased by 100%and 90.8%respectively.The effect of snail control was remarkable,and the Oncomelania snails were effectively controlled.Conclusion:The technical standards of engineering modification and engineering maintenance for schistosomiasis control based on Hankou marshland were successfully developed.Our findings show that environmental modification,mainly through beach and ditch remediation,can completely change the environment of Oncomelania breeding.The implementation of engineering modification and engineering maintenance completed in good condition,and the environment of Hankou marshland was completely transformed,which showed that the molluscicidal effect can accurately reflect the effect of design.Environmental modification combined with mollusciciding was demonstrated to be a better way to control snail transmission in marshland,and snails can be completely eliminated in a short period of time.Engineering maintenance can effectively consolidate the molluscacidal effect of the engineering transformation,and the density of Oncomelania snails can be suppressed in a lower range.