Surveillance of Oncomelania hupensis distribution and water levels in Gaoyou sections of the eastern route project of the South-to-North Water Diversion Project following operation of the project / 中国血吸虫病防治杂志

Objective To understand the distribution of Oncomelania hupensis snails and changes of water levels in Gaoyou sections of the Li Canal following the operation of the eastern route project of the South-to-North Water Diversion Project. Methods The Oncomelania snails were monitored in the river banks and water bodies of Gaoyou sections of the Li Canal by means of systematic sampling combined with environmental sampling as well as collection of the floaters from 2014 to 2019, and the water levels were collected in Gaoyou sections of the Li Canal at the typical hydrological year before the operation of the eastern route project of the South-to-North Water Diversion Project and during the period between 2016 and 2019. Results A total area of 235.42 hm2 were investigated and a total of 75.8 kg floaters were collected in Gaoyou sections of the Li Canal from 2014 to 2019; however, no snails were found. The water level in Gaoyou sections of the Li Canal was predominantly high in the flood season and low in the dry season before the operation of the eastern route project of the South-to-North Water Diversion Project, and the water level was elevated in the dry season and relatively low in the flood season after the operation of the project. Conclusion Following the operation of the eastern route project of the South-to-North Water Diversion Project, the original river bank that is characterized by “land in winter and water in summer” has changed in Gaoyou sections of the Li Canal, which is not favorable for snail breeding.

The South-to-North Water Diversion Project and schistosomiasis: an overview / 中国血吸虫病防治杂志

Before and after the construction of the South-to-North Water Diversion Project, a number of studies have been conducted to assess the possibility of the northward spread of Oncomelania snails and schistosomiasis caused by the construction of the project, the survival and reproduction of snails moved north of their natural distribution, and the transmission of schistosomiasis by the survival snails moved north of their natural distribution. The effect of the South-to-North Water Diversion Project on the transmission of schistosomiasis is restricted along the Jiangsu section of the eastern route project of the South-to-North Water Diversion Project, and the Water Transfer Project from the Yangtze River to Han River of the middle route project of the South-to-North Water Diversion Project. It has been demonstrated the water diversion pattern via the pump stations and the ecological conditions in the water transfusion channels of the South-to-North Water Diversion Project are unlikely to result in the northward spread of Oncomelania snails or schistosomiasis, and no snails or schistosomiasis spread was found during the surveillance before and after the operation of the eastern route project of the South-to-North Water Diversion Project, and the Water Transfer Project from the Yangtze River to Han River of the middle route project of the South-to-North Water Diversion Project. Nevertheless, sustainable surveillance of Oncomelania snails along the South-to-North Water Diversion Project will provide scientific support and safety guarantee for the construction and operation of the subsequent projects.

Water-related diseases along the eastern route of the South-to-North Water Diversion Project / 中国人兽共患病学报

The aim of this study is to investigate the epidemic condition of water-related diseases in the eastern route of South-to-North Water Diversion Project (SNWDP).All data were extracted from published literatures in Chinese about water-related diseases in the eastern route of SNWDP.Pooled analysis was used to explore geographical distribution and epidemiology of the disease.A total of 325 articles about water-related diseases were retrieved during 1953 to 2013,and 209 articles were included in this study.Pooling analysis showed that Shandong Province had the largest number of cases for water-related diseases,following by Jiangsu,Hebei,Tianjin,and Anhui.The numbers of cases were relative small before 1960s according to epidemic curve,and the curve peaked in the 1970s,and decreased after the 1980s.A total of 1 383 834 cases of bacillary dysentery was reported,accounting for 84％ of all water-related diseases on these regions of SNWDP,and followed by hepatitis A,hepatitis E,Japanese encephalitis,typhoid and paratyphoid fever and hemorrhagic fever with renal syndrome.Other reported diseases displayed scatter condition and a small numbers of cases.The prevalence of water-related diseases is sporadic and a trend of decline along the regions of the eastern route of SNWDP.

Analysis of soil components along water channel of east route of South-to-North Water Diversion Project / 中国血吸虫病防治杂志

Objective To explore the relationship between the soil components along the areas of the east route of the South?to?North Water Diversion Project and the survival situation of Oncomelania hupensis snails. Methods Four study sites were se?lected along the project,and soil samples were collected to analyze the components. The amounts of components among the dif?ferent study sites were compared statistically. Results Except zinc,sodium,and phosphorus,the contents of the soil compo?nents where the snails survived were different from those where snails were dead(t=-19.150 to 12.810,all P<0.01). Howev?er,the logistic regression analysis did not obtain a model with statistical significance. Conclusions O. hupensis snails live in the soil with adequate organic matter and neutral pH value. Along with the global warming and the operation of the South?to?North Water Diversion Project,O. hupensis snails may survive in the northern area,and therefore,the surveillance work should be strengthened.

Further study on possibility of diffusion of Oncomelania hupensis with water in river channels of the east route of South-to-North Water Diversion Project / 中国血吸虫病防治杂志

Objective To study the drifting law of floats and potential risks of Oncomelania hupensis diffusion in the water diversion rivers of the east route of South?to?North Water Diversion Project. Methods The O. hupensis snails in the river chan?nels were monitored by the salvage method and snail luring method with rice straw curtains,and the diffusion possibility of snails along with water was assessed through the drift test of floats with GPS. Results In the flood seasons from 2006 to 2013, totally 8 338.0 kg of floats were salvaged,and 2 100 rice straw curtains were put into water in the Li Canal and Jinbao shipping channel,but no Oncomelania snails were found. The drift test of floats with GPS before water diversion showed that the flow ve?locity on water surface(northbound)was 0.45 m/s,the average drift velocity of the floats was 0.56-0.60 m/s,and the average drift distances each time were 999.70- 1 995.50 m in the Gaoshui River section,while there were no obvious drift in Jinbao shipping channel section. During the water diversion period,the flow velocity on water surface(northbound)was 0.45 m/s,the average drift velocity of the floats was 0.35-0.41m/s,and the average drift distances each time were 1 248.06-1 289.44 m in the Gaoshui River,while in Jinbao shipping channel section,the flow velocity on water surface was 0.28 m/s,the average drift velocity of the floats was 0.25- 0.27 m/s,and the average drift distances each time were 477.76- 496.38 m. The drift test showed that the floats gradually closed to the river bank as affected by water flow,wind direction and ship waves,when blocked by the reeds,water plants or other obstacles,and they would stopped and could not continue to drift without outside help. Con?clusions There are no Oncomelania snails found in the river channels of the east route of South?to?North Water Diversion Proj?ect. The drifting distance of the floating debris along with the water is restricted by the flow rate and shore environment.

Surveillance of Oncomelania hupensis snails in source areas of east route of South-to-North Water Diversion Project / 中国血吸虫病防治杂志

Objective To understand the distribution of Oncomelania hupensis snails in source areas of the east route of Southto-North Warter Diversion Project and evaluate the effects of the snails on the safety of water transfer.Methods The investigation of snail distribution was carried out in the source areas of the east route of South-to-North Warter Diversion Project every spring.The method of the random sample combined with environmental sample was used for the field investigation.The beach land in the stilling pool of Jiangdu Pumping Station was selected as a surveillance site to observe the snail spread.Results The areas of the snail habitats and infected snails were 256.11,184.55,164.92,121.16 hm~2 and 8.27,1.0,1.0,0 hm~2 respectively in the source areas of the east route of South-to-North Wafter Diversion Project from 2006 to 2009.The densities of living snails had a downtrend,too.Google Earth showed that the areas of snail habitats distributed mainly in the Jiajiang River and Mangdao River in the source areas.The snail habitats were detected in the beach land in the stilling pool of Jiangdu Pumping Station.The research results showed that the snail spread related to the wastes from the river of drawing water.Conclusion There are the risks of snail spread in the source areas of the east route of South-to-North Wafter Diversion Project,so that the long-term surveillance and control on the snails is very necessary.

Surveillance of schistosomiasis in areas along water transfer project from Yangzte River to Hanjiang River in Qianjiang basin / 中国血吸虫病防治杂志

Objective To evaluate the impact of the water transfer project from the Yangtze River to the Hanjiang River on the transmission of schistosomiasis.so as to provide scientific basis for the development of control strategy.Methods A field investigation on snail status,the infection situation of human and cattle as well as related endemic factors was performed in the project areas of the Qianjiang basin.Results There were 33 endemic villages and 48 non-endemic villages along the water transfer project.In endemic villages,the infection rates of human and cattle were 0.42% and 0.48%,respectively.In the endemic area,the snail area was 17.28 hm~2,the mean density of living snails was 0.043 No./0.1 m~2,meanwhile,no snail Was found in the non.endemic areas.Conclusion The surveillance on epidemic situation should be carried out for a long time in order to prevent the spreading of snails.