Objective To evaluate the cost-benefit of netting cultivation to block the spread of Oncomelania snails in lake re-gions. Methods The cost-benefit of netting cultivation was investigated by interviewing in the field,the cost of Oncomelania snail survey and control was investigated by retrospective review in Gaoyou Lake regions of Jinhu County from 2009 to 2011. The benefit of netting cultivation to block the spread of snails in lake regions was calculated by the benefit-cost ratio(BCR),and then the cost-benefit of them was calculated. Results The area of netting cultivation in Gaoyou Lake regions was 70.77 hm2,the aver-age cost of netting cultivation was 495 595 yuan every year,the average income was 962 000 yuan every year,and the average ben-efit of netting cultivation was 466 405 yuan. The average cost of Oncomelania snail survey and control from 2009 to 2011 was 85 047.87 yuan in Gaoyou Lake regions. The ratio of cost-benefit was 1.11∶1. The benefit was more than the cost. Conclusion There is a well benefit in lake regions during blocking the spread of snails by netting cultivation.

Objective To understand the epidemiological situation of human parasitic diseases in Jinhu County,so as to pro?vide the evidence for formulating further control strategy. Methods The investigated local residents were sampled by the ran?dom cluster sampling method in 1989,1999 and 2015. The infections of intestinal helminthes were detected by Kato?Katz tech?nique,the eggs of Enterubius vermicularis were examined by cellophane anal swab for children,the intestinal protozoa were ex?amined by the saline smear and iodine staining methods. Results The total rates of parasitic infections were 62.57%,9.32%and 0.49%in 1989,1999 and 2015,respectively. Compared to those in 1989 and in 1999,the infection rate in 2015 was de?creased by 99.22%and 94.74%,respectively. The numbers of detected parasite species were 14,10 and 4 in 1989,1999 and 2015,respectively. The intensities of infections were mainly mild in three investigations,and the intensities of all the infections in 2015 were mild. The species of infected parasites were mainly single,however,multiple infections were observed in 1989,in?cluding 4 parasite species(0.72%)and 3 parasite species(7.02%). Only in 1989,the difference between sexes was significant and the infection rate of the female was higher than that of the male(χ2=18.01,P<0.01). Conclusions The infection rates of human parasites are decreased gradually and stabilized at the low level in Jinhu County. However,the surveillance work still should be strengthened to consolidate the achievement.

Objective To evaluate the effect of integrated control measures on soil-transmitted nematodiasis so as to provide the evidence for formulating the appropriate control strategies and measures in Jinhu County,Jiangsu Province. Methods Since 1995,the comprehensive control measures were carried out for soil-transmitted nematodiasis,and the measures included deworm-ing,health education,safe water,sanitation and environmental remediation. The effects of the comprehensive control measures were evaluated by the investigations of the prevalence of soil-transmitted nematodiasis,awareness of health knowledge,and behav-iors of residents. Results From 1995 to 2012,646 437 person-times were administrated in deworming medication with 2.48 times per capita;the benefit rate of safe water was 97.90%;the popularity rate of harmless toilets was 86.89%. The awareness rate of health knowledge increased from 54.05%in 1996 to 95.60%in 2012,the difference between them were statistically significant (χ2=230.92,P<0.01);the rate of correct health behaviors increased from 59.07%in 1996 to 96.40%in 2012,the difference between them had statistical significance(χ2=202.69,P<0.01). The prevalence of soil-transmitted nematodiasis decreased from 62.57%in 1989 to 1.21%in 2012,the difference had statistical significance(χ2=1 016.92,P<0.01). The infection rates of Asca-ris lumbricodes,hookworm and Trichuris trichiura were 0.58%,1.12%and 0,respectively in 2012,and compared with the rates of those infections in 1989,the decline rates were 94.96%,97.28%and 100%respectively,the differences between them were sta-tistically significant(χ2A sc aris =129.50,χ2hookworm=544.62,χ2Tri ch uris =254.19,all P<0.01). Conclusion The comprehensive control strategies and measures are effective and soil-transmitted nematodiasis has been controlled in Jinhu County.

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.