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@#Oncomelania hupensis is the only intermediate host of Schistosoma japonicum. The elimination of Oncomelania snails is the key technique step for schistosomiasis control. This paper summarizes the progress of the techniques of snail control，including the methods of ecology engineering，biology，molluscicides and the study on novel molluscicides，and reviews their features. In addition，this paper explores the appropriate approach to control the snails.
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China's prevention and control of parasitic diseases has made remarkable achievements. However,the prevalence and transmission of parasitic diseases is impacted by the complicated natural and social factors of environment ,natural disas-ters,population movements,and so on. Therefore,there are still the risks of the outbreak of emergency parasitic diseases af-fairs,which may affect the control effectiveness of parasitic diseases and endanger the social stability seriously. In this article , we aim at the analysis of typical cases of emergency parasitic disease affairs and their impacts on public health security in China in recently years,and we also elaborate the disposal characteristics of emergency parasitic disease affairs,and propose the estab-lishment of response system to emergency parasitic disease affairs in China,including the organizational structure and response flow path,and in addition,point out that,in the future,we should strengthen the system construction and measures of the re-sponse system to emergency parasitic disease affairs,so as to control the risk and harm of parasitic disease spread as much as possible and to realize the early intervention and proper disposal of emergency parasitic disease affairs.
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Objective To develop a machine simultaneously integrating mechanized environmental cleaning and automatic mollusciciding and to evaluate its effectiveness of field application,so as to provide a novel Oncomelania hupensis snail control technique in the large?scale marshlands. Methods The machine simultaneously integrating mechanized environmental clean?ing and automatic mollusciciding,which was suitable for use in complex marshland areas,was developed according to the mech?anization and automation principles,and was used for O. hupensis snail control in the marshland. The effect of the machine on environmental cleaning and plough was evaluated,and the distribution of living snails was observed at various soil layers follow? ing plough. The snail control effects of plough alone and plough followed by mollusciciding were compared. Results The ma?chine could simultaneously complete the procedures of getting vegetation down and cut vegetation into pieces,plough and snail control by spraying niclosamide. After plough,the constituent ratios of living snails were 36.31% ,25.60% ,22.62% and 15.48% in the soil layers at depths of 0-5,6-10,11-15 cm and 16-20 cm respectively,and 61.91% living snails were found in the 0-10 cm soil layers. Seven and fifteen days after the experiment,the mortality rates of snails were 9.38% and 8.29% in the plough alone group,and 63.04% and 80.70% in the plough + mollusciciding group respectively(c27 d = 42.74,c215 d =155.56,both P values < 0.01). Thirty days after the experiment,the densities of snails were 3.02 snails/0.1 m2 and 0.53 snails/0.1 m2 in the soil surface of the plough alone group and the plough + mollusciciding group,which decreased by 64.92% and 93.60% ,respectively,and the decrease rate of snail density was approximately 30% higher in the plough + mollusciciding group than that in the plough alone group. Conclusions The machine simultaneously integrating mechanized environmental cleaning and automatic mollusciciding achieves the integration of mechanical environmental cleaning and automatic niclosamide spraying in the complex marshland areas,which provides a novel technique of field snail control in the large?scale setting in Chi?na.
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Objective To explore and integrate the key techniques used in the surveillance and forecast of schistosomiasis in the water regions along the Yangtze River,so as to provide technical support for identifying rapidly the risk of schistosomiasis transmission and implementing control measures targeting the risk. Methods According to the distribution of water systems and water regions along the Yangtze River in Jiangsu Province,the demonstration sites for surveillance and forecast of schistoso? miasis were set across the province,where the integration and demonstration of the techniques regarding monitoring of Schistoso?ma japonicum infection in sentinel mice,human and animal activities,release of forecast information,and emergency treat?ment of water regions at risk of infection were performed. The pattern of human and animal activities was compared with the S. ja?ponicum infection in sentinel mice in the demonstration sites,and the operability of the release of information and emergency treatment of the risk of S. japonicum infection was evaluated. Results A total of 50 demonstration sites for surveillance and forecast of schistosomiasis were set in fixed anchor points,opening of the navigation lock to the Yangtze River,freight terminal, agritainment places,ferry,large construction places,and places for guaranteeing the Youth Olympic Games in 23 counties(dis?tricts)of 5 cities,Jiangsu Province. During the period between May and September,2014,the infectivity of water body was monitored by using 5 batches of sentinel mice,with a 99.06%(4 954/5 001)gross recovery rate of mice. S. japonicum infection was detected in a demonstration site,and an infected mouse was found,with a 0.02%(1/4 933)gross positive rate of sentinel mice. The field survey showed 2 088 person?times contacting water,including 91.95%(1 920/2 088)contacting water due to the production such as capturing fish,harvesting and cultivating crops,and repairing and building boats,and 8.05%(168/2 088)contacting water due to the life activity,such as fishing,washing vegetables and playing with water. The people contacted water predominantly in August and September(49.57%). A total of 859 boats containing 1 877 boatmen were observed,68.22%(586/859)of which were fishing boats containing 1 306 fishermen(69.58%). There were 32 sheep found in 4 demonstration sites,and 3 sheep were seen in the demonstration site with infected sentinel mouse. Four blue forecasts(emergence of water con?tact)and one orange forecast(S. japonicum?infected sentinel mouse detected)were released across the province,with one fore?cast map released which showed 5 sites with fishing and one site with sheep grazing,one emergency response system initiated, mollusciciding implemented in 10 hm2 high?risk regions,120 sheep grazed in fence,and 35 fishermen given health?education materials,schistosomiasis examination and preventive therapy. In addition,no acute schistosomiasis occurred in the demonstra?tion site with S. japonicum?infected sentinel mice. Conclusions The integration and demonstration of the techniques regarding monitoring of S. japonicum infection in sentinel mice,human and animal activities,release of forecast information,and emer?gency treatment of water regions at risk of infection provides an effective approach for the large?scale surveillance and forecast of schistosomiasis.
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Objective To establish the surveillance and risk assessment system of schistosomiasis in Jiangsu Province,so as to provide technical support for timely understanding of the risk of schistosomiasis transmission and implementation of target-ed control measures. Methods The surveillance sites of schistosomiasis were assigned according to the epidemic status and en-demic type of schistosomiasis as well as the characteristics of the water system,and the prevalence of Schistosoma japonicum in humans and domestic animals,and snail status were investigated. In addition,the quality control of serum detection of S. japon-icum infections was performed. The prevalence of human and animal S. japonicum infections,snail status and missing diagnosis of serum detection were analyzed and compared among regions. Results A total of 27 surveillance sites of schistosomiasis were set up in 26 counties of 10 cities,Jiangsu Province,including 14 sites in transmission-interrupted villages and 13 sites in trans-mission-controlled villages,and 15 sites in marshland and lake regions,9 sites in plain regions with water network and 3 sites in mountainous region. In the 27 surveillance sites,a total of 16 617 residents were screened for S. japonicum infection by using dipstick dye immunoassay(DDIA),and 326 were sero-positive,with a sero-prevalence of 1.96%(2.17%for men and 1.8%for women). Of the 326 individuals undergoing parasitological examination,2 positive cases were detected in the marshland and lake region,with a S. japonicum human prevalence of 0.01%. Of the 762 floating population detected,10 were positive for blood test,with a sero-prevalence of 1.31%,and no egg-positive individuals were detected. No infection was found in the 476 do-mestic animals. Of the 746 settings surveyed,a total of 240.7 hm2 snail area was detected,with a mean snail density of 0.06 snails/0.1 m2,and no infected snails were found. There were 780 quality-control sera detected in 26 surveillance sites of schisto-somiasis,and the gross coincidence rate was 95.13%,with misdiagnosis rate of 1.28%and missing diagnosis rate of 19.23%. Conclusion The surveillance sites of schistosomiasis show reasonable distribution in Jiangsu Province,and the endemic situa-tion of schistosomiasis appears a low level in the whole province.
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Schistosomiasis is a neglected tropical disease that severely threatens human health and affects the socioeconomic development. The causative agent that parasitizes in humans mainly involves Schistosoma japonicum,S. mansoni,S. haematobi-um,S. intercalatum and S. mekongi. As the firstly identified schistosome,S. haematobium infection is found to strongly correlate with bladder cancer. This paper mainly reviews the discovery,morphology and life cycle of S. haematobium.
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Objective To evaluate the outcomes of implementation of integrated schistosomiasis control strategy with empha? sis on infectious source control using a bibliometric method. Methods The literature pertaining to integrated schistosomiasis control strategy with emphasis on infectious source control was retrieved from CNKI,Wanfangdata,VIP,PubMed,Web of Sci? ence,BIOSIS and Google Scholar,and a bibliometric analysis of literature captured was performed. Results During the period from January 1,2004 through September 30,2014,a total of 94 publications regarding integrated schistosomiasis control strate? gy with emphasis on infectious source control were captured,including 78 Chinese articles(82.98%)and 16 English papers (17.02%). The Chinese literature was published in 21 national journals,and Chinese Journal of Schistosomiasis Control had the largest number of publications,consisting of 37.23% of total publications;16 English papers were published in 12 interna? tional journals,and PLoS Neglected Tropical Diseases had the largest number of publications(3 publications). There were 37 affiliations publishing these 94 articles,and National Institute of Parasitic Diseases,Chinese Center for Disease Control and Pre? vention(16 publications),Anhui Institute of Schistosomiasis Control(12 publications)and Hunan Institute of Schistosomiasis Control(9 publications)ranked top three affiliations in number of publications. A total of 157 persons were co?authored in these 94 publications,and Wang,Zhou and Zhang ranked top 3 authors in number of publications. Conclusion The integrated schistosomiasis control strategy with emphasis on infectious source control has been widely implemented in China,and the achievements obtained from the implementation of this strategy should be summarized and transmitted internationally.
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Objective To analyze the characteristics and changes of Oncomdania snail distribution in regions with different epidemic types and degrees of Jiangsu Province,so as to provide the evidence for implementing the feasible schistosomiasis control strategy.Methods A retrespeetive survey was performed,and the 5-year database of snail status in Jiangsu Province was established based on the collected reports of snail habitat cards and schistosomiasis control in Jiangsu Province from 2004 to 2008.The changes of snail areas,infected snail aroas,infection rates of snails in different years were analyzed,and tIIe annual vailations of snail areas,infected snail areas and infection rates of snails in areas with different epidemic types and degrees were eomparedI Results The actual snail areas and infected snail areas decreased by 3 799.86 hm~2 and 2 006.35 hm~2.respectively in Jiangsu Province.2006-2008.with the annual meaan decreasing rates of 9.64% and 18.83%.Among them,the actual snail areas in marshland and lake regions,water net regions and mountainous regions decreased by 3 546.10.209.19 hm~2 and 44.57 hm~2,respectively,with the annual meall decreasing rates of 9.59%,10.29% and 11.18%,respectively.An area of 22.02 hm~2 of new snail habitatswas detected during the 5 years,and thewater net regions accounted for 89.24%.Theproportions of actual snail areas in historical snail ale,as were between 2.77% and 5.36%.Among them.the proportions of actual snail areas in historical accumulative snail area8 in transmission-uncontrolled.trailsmission-controlled and transmission-interrupted areas were 13.29%-22.82%,0.88%-3.54% and 0.14%-0.32%,respectively,and there were significant differences among them(P<0.01).The constituent ratios of the actual snail areaswere 93.79%-95.60%.3.67%-5.45% and 0.73%-1.01%, respectively in marshland and lake regions,water net regions and mountainous regions from 2004 to 2008.The infection rate of snails in Jiangsu Province reduced from 0.15% in 2004 to 0.02% in 2008,with a reduction rate of 85.50%(P<0.01).The constituent ratios of infected snail areas in transmission-uncontrolled, transmission-controlled and transmission-interrupted areas were 98.15%-100%,0-0.81%, and 0-1.43%,respectively.Conclusions As a whole,there is a decreasing tendency of snail areas and infected snail areas in Jiangsu Province.and the snail control has been consohdated step by step in transmission-interrupted areas.The effective control of snails in marshland and lake regions and infected snails in transmission-uncontrolled areas are the key points in the future schistosomiasis control of Jiangsu Province.
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The surveillance of schistosomiasis in Sanzhou Village, Dantu District, Zhenjiang City, a national schistosomiasis surveillance site, showed that in 2008, the area with snails was 27 hm~2, among which the area with infected snails was 14 hm~2, the densities of living snails and infected snails were 0. 86 and 0.002 1 snails/0. 1 m~2, respectively. The infection rate of snails was 0.25% , the positive rate of IHA was 3. 10% and the infection rate of schistosome in human populations was 1%. There were no infected domestic animals found, and there were no acute schistosomiasis and newly advanced schistosomiasis cases found in the surveillance site in 2008. It is indicated that the endemic situation of schistosomiasis is stable. The comprehensive control, including molluciciding and environmental modification, should be implemented for snail control. The comprehensive measures with emphasis on infectious source control should be further strengthened.
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<p><b>OBJECTIVES</b>To perform GIS spatial analysis on malaria transmission patterns in Jiangsu after setting up a malaria database and developing GIS model of malaria transmission in Jiangsu province.</p><p><b>METHODS</b>The epidemiological GIS database of malaria in Jiangsu province was established using ArcView 3.0a software. The climate data covering Jiangsu province and its peripheral area were extracted from the FAOCLIM database, the total growing degree days (TGDD) for Plasmodium vivax were calculated, and spatial distribution for TGDD was analyzed by ArcVeiw 3.0a.</p><p><b>RESULTS</b>The predicted malaria distribution map based on TGDD was created, which showed that the transmission of malaria decreased gradually from west to east, which can be divided into three belts according to the degree of transmission. The 14-year mean morbidity distribution map of malaria in Jiangsu showed that the middle and west parts of Jiangsu is the most serious endemic area. The morbidity in the areas along the Taihu valley, such as Suzhou, Wuxi and Changzhou, as well as Nantong and a few of northern counties are the lowest. The morbidity of other places is at the middle level. The 14-year mean morbidity distribution map of malaria is correlated with predicted malaria distribution map for TGDD.</p><p><b>CONCLUSION</b>It is possible to monitor the malaria transmission by GIS predicted model based on TGDD.</p>
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Humans , China , Epidemiology , Databases, Bibliographic , Geographic Information Systems , Malaria , Epidemiology , Models, BiologicalABSTRACT
Objective To study the impact of environmental temperature on the development of Schistosoma japonicum larvae within the Oncomelania hupensis. Methods Oncomelania snails, collected from the field and free of S. japonicum infection, were exposed to miracidiae of S. japonicum in a ratio of 1∶20 and raised at 30 ℃, 27 ℃, 24 ℃, 21 ℃ and 18 ℃, respectively. The prepatent period of larvae within the Oncomelania hupensis and the developmental velocity were determined, of which the relationship with the temperature was analysed. Results The average prepatent period of cercariae in snail was (128.89?16.05) d,(95.00?21.03) d,(71.93?12.74) d and (62.74?14.19) d at 21 ℃, 24 ℃, 27 ℃, 30 ℃, respectively. The regression formulation between prepatent period and temperature was y =730.68x -0.8918 (r=0.9976, P
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A total of 13 allozymes of 7 populations of Oncomelania snails trom 7 provinces in the mainland China were examined by horizontal starch gel electrophoresis. Results demonstrated that out of 17 loci examined, 10 were monomorphic loci: Aldh,Ao,G6pd ,Gpdh,Hbdh,Ldh, Sdh,Est-2,Est-3,and Est-6,and 7 were polymorphic loci:Est-4,Est-5,Xdh,Mdh,Idh,Got and Ap. Banding pattern showed that six enzymes were polymorphic accounting for 46.15 % (6/13) of total enzyme systems examined. Results indicated that a certain of relative relation-ship was existed along with the significant variation presented based on their environment and location among the 7 populations of snails from the mainland of China. It was revealed that the 7 polymorphic loci were the important loci affecting the gentic variation in the differ-ent populations of Oncomelania spp.
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Objective To evaluate the molluscicidal effect and the using value of qiangluocide powder by dusting in the fields. Methods The two different ways of dusting with qiangluocide and spraying with luomiecide for controlling snails were compared in the fields, and the cost-effectiveness was analysed. Results The corrected mortalities and the reduced rates for density of snails were 88.48%, 96.26%, 96.96%, 95.67%, and 87.58%, 95.40%, 96.14%, 96.67%, respectively, on the marshland in Longtan, Nanjing, 73. 65% , 98. 31% , 99. 22% , 99. 26% and 69. 30% , 98.14%, 98.84%, 98. 60% , respectively, on the marshland in Yizheng, Yangzhou, on 1 d, 3d, 7 d, 15 d after dusting with qiangliocide power; and those on 1d, 3d, 7d, 15d after the spraying with luomiecide were 69.15%, 88.01%, 86.46%, 85.56% and 75.27%, 84.99%, 87.50%, 87.96% on the marshland in Longtan, Nanjing, 18.70%, 63.11%, 1.25%, 12.60% and 34. 88% , 89. 02% , 45.37% , 46. 59% , respectively, on the marshland in Yizheng, Yangzhou. The st of dusting with qiangluocide powder was 0. 20 yuan/m2, and that of spraying with luomiecide as 0. 21 yuan/m2 for snail control in the fields. The costs of reduced one percentage for the cor rected mortalities and the density of snail were 6. 27-10. 07 yuan and 6. 21-10. 14 yuan, respectively, on 15 d after dusting with qiangluocide power and those on 15 d after spraying with luomiecide were 7. 36-83. 33 yuan and 7. 16-22. 54 yuan , respectively. Conclusion The dusting with qiangluocide powder is a promising new formulation, which is suitable for the areas without water resource and possessed of high effectiveness against snails. The method ofdusting with qian-gluocide powder for controlling snails is simple, convenient, cheap and easy to be carried out for the inspection and quality control.
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Objective To determine the de ve lopmental zero and effective accumulated temperature of Oncomela nia eggs under con stant temperature. Methods The eggs were cultur ed under different constant temperature, and their development duration and effe ctive accumulated temperature were studied. The zero accumulated temperature (℃ ) was obtained by using an estimation mode, and the effective accumulated temp erature was obtained by effective accumulated mode of K=N(T-C). [WT5”H Z] Results The average development duration was (27.29?17 .2 9) d under 15-30 ℃, the development zero temperature was 11.79 ℃ and 38.22 ℃ u nder low and high temperature respectively, and the average development temperat ure and effective accumulated temperature were (557.76?198.95) DD and(236 .02 ?68.20) DD.Conclusion The suitable developme nt temperature of eggs is 27 ℃, the development speed and effective accumulated t e mperature of eggs increases with the temperature under given condition, but too high temperature may have negative impact on the development of eggs. The resul t can be considered as the basic biological parameter of the snail.
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Objective To identify the trend of endemic situation among surveillance sites in Jiagsu Province from 2000 to 2002. Methods Twelve schistosomiasis surveillance sites were es-tablished ,and the longitudinal, surveillance was carried out. Results The related index of snail increased in most of surveillance sites, the rates of positive snails rose rapidly in marshlands. The infection rates of Schitosoma janponicum of cattle decreased and infection rates of human were relatively steady. However, there was still the danger of heavy endemic. Conclusion Current control strategies can not effectively adapt to the endemic situation of schistosomiasis, although which have some effects on control of morbidity. We need to study the new characteristics and rule of the endemic of schistosomiasis, and make out more effective control strategies which can suit with the current society, economies and nature environment.
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Objective To design the Internet geographic information system (GIS) on schistosomiasis of Jiangsu Province using the technology of WebGIS. Methods Based on the GIS database of schistosomiasis, the active model of WebGIS on schistosomiasis was developed with the software of ArcIMS. Results The WebGIS of schistosomiasis has been developed and it has been running on the intranet of Jiangsu Institute of Parasitic Diseases. The system would manage the geographic database and attribute material database, and it would provide the function of query, display, analysis, statistics, export, etc. Conclusion It is feasible to design the WebGIS of schistosomiasis, which provides the basics of developing the Management Decision Systems of Schistosomiasis of Jiangsu Province.
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Objective To explore the rela ti onship between the environmental temperature and the oxygen demand of [WT5” BX]Oncomelania snails, and the relationship between the hiber nation or aestivation and the oxygen demand of snails.Me thods The oxygen demand of Oncomelaniasnails between 0 ℃ and 40 ℃ was determined by increasing the temperature gradually in lab, the relationship between the environmental tempera ture and the oxygen demand, and the correlative relationship between the oxygen demand and the percentage of snails in hibernation or aestivation were analysed. Results The oxygen demand increased as the tem perature rose between 1 ℃ and 36 ℃, and the regression equation between the oxygen demand and the variation of environmental temperature was [WT5”BX ]=6.6?10 -5-3?10 -6x+4.4?10 -6x2-8?10 -8x 3(R2=0.998,F=2775,P
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0.05.Therefore,the average EGDD of S.japonicum developing in snails from the Yangtze River basin was 631.44 degree days, with its 95% confidence interval from (426.76 - 836.12) degree days. Conclusion The EGDD of S.japonicum developing in different snail populations along the Yangtze River are quite similar.
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Objective To evaluate the eff ec t of snail control with niclosamide ethanolamine salt dustable powder (DP) in th e marshland of the Yangtze River ahead of the schedule in spring, and to underst and the impact of the low temperature to molluscicidal effect of the dusting. Methods The snail control test with niclosamide ethanolamine salt dustable powder was carried out under different te mperatures in laboratory. Then the snail control was undertaken in the marshland of the Yangtze River ahead of the schedule in spring, and the molluscicidal ef fect was observed and the temperature changes were also considered. Results When the temperature was 15 ℃ and 25 ℃ respectively, there was no significant difference on the molluscicidal effec t of niclosamide ethanolamine salt DP in laboratory. The average atmosphere temp erature in each day was 8.9-16.3 ℃ from the last ten-day of March to the fir st ten-day of April in Nanjing regions. The corrected mortality of snails and the r educed rates of density of snails were 95.38% and 99.97% respectively on the s ur face of the soil in the marshland field. The corrected mortality and the reduced rates of density of snails were 79.30% and 70.59% respectively in the surface l ayer of the soil. Conclusion The impact of air t emperature is little to the molluscicidal effect of niclosamide ethanolamine sal t DP when the average atmosphere temperature in each day was 10-15 ℃ in the ma r shland of the Yangtze River. If the snail control is undertaken ahead of the sch edule in spring, the reproduction of snails will be suppressed and the infection of Schistosma japonicum will be controlled. [
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Objective To evaluate the mid-term effectiveness of the medium-and-long-term programme of the prevention and control of schistosomiasis in Jiangsu Province. Methods The programme was carried out in Jiangsu Province and the comprehensive measures relied mainly on snail control, detection and chemotherapy of schistosomiasis for residents and livestock. The mid-term effectiveness of the programme was observed and evaluated longitudinally. Results The coverage rate of snail control areas and the ratio of chemotherapy of schistosomiasis for residents and livestock rose year after year. The snail areas, the infected snail areas and the infection rate of schistosome for residents and livestock reduced year after year. There were negative correlations between the coverage rates of snail control and the infected snail areas, the number of settings with infected snails, the infection rate of schistosome for residents, the infection rate of schistosome for livestock and the morbidity of acute schistosomiasis, respectively (rInfected snail areas=-0.897,P=0.039;rNo. of settings with infected snail=-0.937,P=0.019;rInfection rate for residents=-0.913,P=0.031;rInfection rate for livestock=-0.991,P=0.001;rMorbidity of acute schistosomiasis=-0.894,P=0.041). There were negative correlations between the ratio of chemotherapy of schistosomiasis for residents and the infected snail areas, and between the ratio of chemotherapy of schistosomiasis for livestock and the infected snail areas (rRatio of chemotherapy for residents =-0.965,P=0.008;rRatio of chemotherapy for livestock=-0.921,P=0.027). There were negative correlations between the funds of schistosomiasis control and the infection rate of schistosome for residents livestock, respectively (rInfection rate for residents=-0.897,P=0.039;rInfection rate for livestock=-0.971,P=0.006). The multiple linear regression analysis showed that there were the linearity relationships between the infection rate of schistosome for residents and the coverage rates of snail control, and between the infection rate of schistosome for livestock and the coverage rates of snail control, and between the morbidity of acute schistosomiasis and the coverage rates of snail control. Conclusions The effect of the comprehensive strategy of schistosomiasis control which relies mainly on snail control, detection and chemotherapy of schistosomiasis for residents and livestock are remarkable. The snail control and chemotherapy are effective and immediate. The increased funds would be essential guarantee for control and elimination of schistosomiasis.