ABSTRACT
Objective To evaluate the molluscicidal effects of different formulations of niclosamide ethanolamine salt in marshlands. Methods The molluscicidal effects of spraying with 25% suspension concentrate of niclosamide ethanolamine salt (25% SCN) and 50% wettable powder formulation of niclosamide ethanolamine salt (50% WPN), and dusting with 4% niclosamide ethanolamine salt dustable powder (4% DP) for controlling Oncomelania hupensis snails were investigated and compared in the fields, and the cost-effectiveness was analyzed. Results The corrected mortalities and the reduced rates of density of snails were 54.37%, 91.70%, 92.76%, 79.50%, and 59.55%, 95.93%, 97.63%, 94.15%, respectively, on 3, 7, 15, 30 d after spaying with 25% SCN, those on 3, 7, 15, 30 d after dusting with 4% DP were 59.10%, 91.83%, 95.56%, 93.34% and 65.03%, 94.93%, 97.61%, 97.28%, respectively; and those on 3, 7, 15, 30 d after spraying with 50% WPN were 76.29%, 91.68%, 93.12%, 81.59% and 81.24%, 97.02%, 97.84%, 95.27%, respectively. The cost of spraying with 25% SCN was 0.21 Yuan/m2, that of dusting with 4% DP was 0.39 Yuan/m2, and that of spraying with 50% WPN was 0.23 Yuan/m2 for snail control in the marshland. The cost of reduced one percentage of the corrected mortalities and the density of snails in controlling snails by 25% SCN, 4% DP and 50% WPN on 15 d were 22.68, 40.63, 25.17 Yuan and 21.54, 39.78, 23.95 Yuan, respectively. Conclusions The three different formulations of niclosamide are reliable and effective for snail control in marshlands. There are some differences among the different molluscicides in start time, pharmacodynamic characteristics, spraying methods in the field, cost of snail control, and influencing factors. Therefore, we need reasonably select the suitable molluscicides according to the environmental characteristics and working condition.
ABSTRACT
Objective To evaluate the molluscicidal effects of different formulations of niclosamide ethanolamine salt in marshlands. Methods The molluscicidal effects of spraying with 25% suspension concentrate of niclosamide ethanolamine salt (25% SCN) and 50% wettable powder formulation of niclosamide ethanolamine salt (50% WPN), and dusting with 4% niclosamide ethanolamine salt dustable powder (4% DP) for controlling Oncomelania hupensis snails were investigated and compared in the fields, and the cost-effectiveness was analyzed. Results The corrected mortalities and the reduced rates of density of snails were 54.37%, 91.70%, 92.76%, 79.50%, and 59.55%, 95.93%, 97.63%, 94.15%, respectively, on 3, 7, 15, 30 d after spaying with 25% SCN, those on 3, 7, 15, 30 d after dusting with 4% DP were 59.10%, 91.83%, 95.56%, 93.34% and 65.03%, 94.93%, 97.61%, 97.28%, respectively; and those on 3, 7, 15, 30 d after spraying with 50% WPN were 76.29%, 91.68%, 93.12%, 81.59% and 81.24%, 97.02%, 97.84%, 95.27%, respectively. The cost of spraying with 25% SCN was 0.21 Yuan/m2, that of dusting with 4% DP was 0.39 Yuan/m2, and that of spraying with 50% WPN was 0.23 Yuan/m2 for snail control in the marshland. The cost of reduced one percentage of the corrected mortalities and the density of snails in controlling snails by 25% SCN, 4% DP and 50% WPN on 15 d were 22.68, 40.63, 25.17 Yuan and 21.54, 39.78, 23.95 Yuan, respectively. Conclusions The three different formulations of niclosamide are reliable and effective for snail control in marshlands. There are some differences among the different molluscicides in start time, pharmacodynamic characteristics, spraying methods in the field, cost of snail control, and influencing factors. Therefore, we need reasonably select the suitable molluscicides according to the environmental characteristics and working condition.
ABSTRACT
Objective To evaluate the molluscicidal effect of suspension concentrate of niclosamide ethanolamine salt(SC-NE)against Oncomelania hupensis snails in laboratory and field. Methods The experiment of SCNE against the snails by using the immersing and spraying methods was performed in laboratory and field,with control groups of wettable powder of ni-closamide ethanolamine salt(WPN). Results In the laboratory,LC50(s) of SCNE for 24,48 h and 72 h by using the immersion method were 0.0926,0.0629 mg/L and 0.0549 mg/L,respectively. The mortality rates of snails for 24,48 h and 72 h by using the immersion method were all 100% with the concentrations of 0.25 mg/L. The mortality rates of snails were all 100% while spraying SCNE for 3 d in the laboratory with the concentrations of 0.25 g/m2. In Jiangling County,except 0.5 g/m3 SCNE immers-ing the snails for 24 h,the mortality rates of snails by using SCNE with the immersing method were all 100%. While the concen-tration of SCNE was 0.5 g/m3 or above,the mortality rates were all 100%after the use of it with the immersion method for 2 d in Gong'an County. In Jiangling County,the mortality rates of snails by using SCNE 0.5 g/m3 for 1 d,3 d,and 7 d with the spray-ing method were 87.5%,92.82%and 97.40%respectively. While the concentration of SCNE was 0.5 g/m3,the mortality rates were 85.94%,86.78%and 94.21%respectively after the use of it with the spraying method for 1 d,3 d,7 d in Gong'an Coun-ty,and the molluscicidal effect of SCNE(1.0 g/m2)was higher than that of WPN. Conclusion SCNE has a high molluscicidal effect in the laboratory and field,and it is a novel and simple formulation of niclosamide.
ABSTRACT
Relevant projects carried out within the Yangtze River economic belt on the impact of schistosomiasis epidemic and transmission are important issues for ecological priority in the process of implementing the strategy. The key problems of schistosomiasis epidemic risk,epidemic happening repeatedly,difficulty of rehabilitating Oncomelania hupensis snail control and schistosomiasis prevention forest,lag of evaluation system and platform construction,lack of basic research,et al. were ana-lyzed in the Yangtze River economic belt taking ecological priority as the basis in this paper. Then corresponding countermea-sures to these challenges were put forward so as to provide the reference for the national forestry schistosomiasis control pro-grams,which include:execution of the comprehensive prevention and control strategy,scheming of the new round of forestry schistosomiasis control programs,strengthening schistosomiasis prevention and control,promoting productivity in existing forest-ry to consolidate and improve the achievements of previous forestry schistosomiasis control programs,and promoting the intensi-ty of technological innovation to improve the technological level of forestry schistosomiasis control programs.
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Objective To analyze the investigation data of the national schistosomiasis surveillance sites in 2015,so as to provide scientific evidences for schistosomiasis control,elimination and surveillance. Methods According to National Schisto-somiasis Surveillance Programme(version 2014),457 surveillance sites were selected,and the investigation data in residents, floating population,domestic animals and Oncomelania hupensis snails were collected and analyzed from four types of endemic counties. Results A total of 4468 seropositive cases were detected from 133350 residents,among which 4457 residents with seropositive results received the etiological tests,and 71 of them were identified with positive results. Most of them were fisher-men and farmers in the middle and old-aged group. The schistosomiasis infection rate was 0.05% in local population. Totally 977 seropositive cases were examined from 85047 migrant individuals,and 16 positive cases were found out from 966 individuals who took etiological tests,which showed the schistosomiasis infection rate was 0.02% in floating population. Imported cases were found among floating people in four provinces,namely Zhejiang,Hunan,Hubei and Anhui provinces. No acute schistoso-miasis cases were reported. A total of 13406 head of cattle received examinations and only 5 were determined as stool positives. The cattle infection rate was 0.04%. The snail survey covered an area of 22295.13 hm2 and snails were found in an area of 7426.63 hm2,including 3.47 hm2 newly detected area with snails. No schistosome-infected snails were found. Conclusions Based on the collected data from 457 national schistosomiasis surveillance sites of China,the Schistosoma japonicum infection rate is 0.05% in local population which maintains a stably descending trend. In floating population,there are imported schistosome-in-fected persons. Cattle are still a vulnerable species infected with schistosome. Although no infected snails are found,snails are widely distributed in endemic areas. Some provinces detect areas with snails for the first time or the reproduction of snails. The staff in endemic provinces should carry out the surveillance work according to National Schistosomiasis Surveillance Programme (version2014)to improve the surveillance system,and enhance the sensibility and effectiveness of surveillance work.
ABSTRACT
Objective To investigate the effects and cost of four formulations of niclosamide ethanolamine salt in Oncomela-nia hupensis snail control in the field in marshland and lake regions,so as to provide the evidence for drawing up the plan of mol-luscicide using in schistosomiasis endemic areas. Methods One drainage channel and one channel without water in the same area with snails in Jiangling County,Jingzhou City were selected as the research fields. The drainage channel was divided into 9 sections,except one section as a blank control group where the natural death rate of snails was observed only,and the remaining 8 sections were taken as the observation groups,where different dosages of 4%niclosamide ethanolamine salt powder,5%ni-closamide ethanolamine salt granules,25% niclosamide ethanolamine salt suspending agent,26% metaldehyde and ni-closamide ethanolamine salt suspending agent,and 50%niclosamide ethanolamine salt wettable powder were used re-spectively. The channel without water were divided into 4 sections,except one section as a blank control group,the oth-er 3 segments were taken as the observation groups,where 4%niclosamide ethanolamine salt powder,5%niclosamide ethanolamine salt granules,and 50% niclosamide ethanolamine salt wettable powder were used respectively. Before and after spraying molluscicide for 7 days and 15 days,the system sampling method was used to observe the effects of snail control. Meanwhile,the unit cost method was used to calculate the costs of the different mulluscicide formulations abovementioned in unit area(1 m2). Results In the field at the drainage channel,the snail mortality rates of the groups spraying 4%niclosamide ethanolamine salt powder(50 g/m2),5%niclosamide ethanolamine salt granules(40 g/m2),25% niclosamide ethanolamine suspending agent,26% metaldehyde and niclosamide ethanolamine salt sus-pending agent,and 50%niclosamide ethanolamine salt wettable powder(2 g/m2 and 4 g/m2)for 7 days were 79.52%-97.87%,while the rates after spraying for 15 days were 71.00%-96.30%,and compared with those before spraying, the differences were statistically significant(all P<0.01). For the groups spraying with 2 g/m2 or 4 g/m2 suspending agent as well as wettable powder for 7 days,the snail mortality rates were significantly different(both P<0.05). In the field at the channel without water,the snail mortality rates of the 3 observation groups after spraying molluscicide for 7 days were 97.14%-100%,while for 15 days were 94.32%-100%,and compared with the rates before spraying,all the differences were statistically significant(all P<0.01). The unit costs per 1 m2 of the molluscicide abovementioned were ranged from 0.280 Yuan to 0.416 Yuan. Conclusions In marshland area inside embankment,the molluscicide formulations of the powder and granule are suitable for the environments without water or with instability water level , while the molluscicide formulations of the suspended agents and wettable powder are suitable for the water environment. Though the unit cost of powder is the lowest,the molluscicide in this formulation flies away seriously.
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Objective To understand the risk situation of imported schistosomiasis and its main influencing factors in Shang-hai City from 2005 to 2015. Methods A retrospective survey was performed,and the database was established based on the da-ta collection of imported schistosomiasis,Oncomelania hupensis snail situation and mobile population in Shanghai City from 2005 to 2015. Results From 2005 to 2015,the mobile population in Shanghai City increased by 123.92%,which reached about 9816500,and 54.70%of them were located in the inner suburban districts. The accumulated areas with snails of 7.13 hm2 were found in 16 towns of 4 outer suburbs(excluding Chongming District). A total of 23 cases of imported schistosomiasis were found in Shanghai City,and the number of the imported schistosomiasis cases was on the downward trend(rs=-0.782,P=0.004). From 2005 to 2009,11 out of 13 imported schistosomiasis cases(84.62%)were distributed in the inner suburban dis-tricts where no O. hupensis snails were found at the same time. From 2010 to 2015,9 out of 10 imported schistosomiasis cases (90%)were distributed in the outer suburban districts where O. hupensis snails were found at the same time. Conclusion The number of imported schistosomiasis cases in Shanghai is on the downward trend. However,the threat of imported schistosomiasis to the prevention and control of schistosomiasis in Shanghai City should not be ignored.
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Objective To explore the strategy and countermeasures of Oncomelania hupensis snail control and evaluate the effect in inside-embankment areas of lake-type schistosomiasis endemic area,for providing the effective method for controlling and interrupting the schistosomiasis transmission. Methods The data of schistosomiasis epidemic and its control and preven-tion were collected in Junshan District,Hunan Province,and the effect of snail control countermeasures were evaluated and the trend of indexes of snails was drafted in the inside-embankment areas of Junshan District,Hunan Province from 1998 to 2007. Results The area with snails in the inside embankment areas of Junshan District decreased by 98.43%,from 1496.66 hm2 in 1998 to 23.48 hm2 in 2017. The occurrence rate and average density of of living snails decreased from 20.61%and 0.45 snail/0.1 m2 in 2003 to 2.06%and 0.03 snail/0.1 m2 in 2017. The highest area with schistosome infected snails was found in 2001 and the total area was 79.36 hm2,however,no infected snails were found since 2007. The total fiscal investment for schistosomiasis pre-vention and control was 398.857 million RMB in Junshan District,including molluscicide(81.7709 million RMB)and environ-ment reform(213.5 million RMB)respectively. Conclusion The comprehensive measures,mainly including the combination of molluscicide and environment reform have gotten a significant effect in snail control and elimination in the inside-embankment areas,but the snail surveillance still need to be strengthened in the historic areas with snails.
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Objective To observe the Oncomelania hupensis snail control effects of molluscicides with different formula?tions in the ditch with unstable water level in field of marshland and lake areas,so as to provide the evidence for formulating the prevention strategies. Methods A drainage channel with O. hupensis snails in Jiangling County,Jingzhou City were selected as the study field,then it was divided into 6 segments,except 1 segment was treated as the blank control group for observing the natural mortality rate of the snails,the other 5 segments were treated as observation groups,where 4% niclosamide ethanol?amine salt powder,5%niclosamide ethanolamine salt granule,25%suspension concentrate of niclosamide ethanolamine salt, 26% suspension concentrate of metaldehyde and niclosamide ethanolamine salt,50% niclosamide ethanolamine salt wettable powder were applied respectively. Before and after the mollusciciding,the snail surveys were carried out through the systematic sampling method,and the short?and long?term effects of snail control were observed,and the mortality rates of the snails on the slope above the water level and those below the water level were compared. Results When 7 d and 15 d after mullusciciding, the mortality rates of snails on the slope above the water level in each observation group were 79.52%-97.87% and 90.43%-96.30%,respectively,when compared with those before mollusciciding,all the differences were statistically significant(all P<0.01). When 7 d after mullusciciding,the mortality rates of snails below the water level in each observation group were 17.11%-50.00%,which were all lower than those of the snails on the slope above the water level in the corresponding groups(all P<0.05);when 15 d after mullusciciding,the rates were 9.43%-95.24%,and those in 25%suspension concentrate of niclosamide ethanolamine salt,26%suspension concentrate of metaldehyde and niclosamide ethanolamine salt,50%niclosamide ethanol?amine salt wettable powder groups were all lower than those of the snails on the slope above the water level in the corresponding groups(all P<0.01). Compared with the densities of living snails before mollusciciding,those 6 months after mollusciciding in each observation group decreased by 70.21%-78.98%. Conclusions The molluscicides in the formulation of powders and granule are suitable for both the snail environment with or without water,while those in the formulation of suspension agents and wettable powders are suitable only for environments with water.
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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.
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Objective To explore the changing rule of schistosomiasis endemic situation in Gaoyou City,so as to provide the evidences for schistosomiasis control in lake and marshland regions. Methods The endemic data of schistosomiasis of Gaoy?ou City from 1970 to 2009 were collected to analyze the endemic patterns of schistosomiasis in different control stages compre?hensively. Results In the first years of infection control stage(1970-1975),transmission control stage(1976-1994)and transmission interruption stage(1995-2009),the prevalence rates of schistosomiasis were 4.20%,0.80%and 0 in human and 3.00%,0.51%and 0 in cattle respectively. In 1984,the positive rate of crowd stool tests fell to 0.04%,which was reduced by 99.05%compared with that in 1970. From 1970 to 1980,the positive rates of stool tests of people and livestock were positively correlated significantly(r=0.67,P<0.05). After 1985,no local infection patients or cattle were found. No schistosome infect?ed Oncomelania hupensis snails were found from 1970 to 2009. Conclusion The comprehensive control measures have been insisted in Gaoyou City in different prevention and control stages. Although the snail situation is undulate,the prevalence of schistosomiasis steadily declines and the interruption of transmission has achieved.
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Objective To analyze the endemic situation of schistosomiasis after its interruption of transmission in Xiuzhou District,Jiaxing City,Zhejiang Province,so as to provide the references for future surveillance work. Methods The data of schistosomiasis and Oncomelania hupensis snails in Xiuzhou District were collected and analyzed statistically. Results From 1994 to 2015,totally 975 village?times were investigated for O. hupensis snails,and the accumulated area of 4 385.31 hm2 was surveyed. Twenty former snail sites were reoccurring,with an area of 32.61 hm2. An area of 57.71 hm2 was supplied with snail eradication measures. Totally 11 941 snails were dissected and no schistosome infected snails were found. The serum and stool tests were performed to 221 794 and 3 731 residents respectively,and no local infection cases but four imported cases were found. Conclusion The endemic situation of schistosomiasis in Xiuzhou District is stable after the transmission was interrupt?ed. However,there are imported schistosomiasis cases,and therefore,the prevention of imported infection source is the focus of surveillance work.
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Objective To evaluate the effect of wild feces detection in Oncomelania hupensis environments on the surveil?lance of infection source of schistosomiasis,and find the weakness in schistosomiasis control in Hubei Province,so as to put for?ward the targeted strategies and measures. Methods Four environments with O. hupensis snails in endemic areas of Hubei Provinces,where human and livestock often haunted,were selected according to the river systems,namely the Juzhanghe River beach in Jingzhou City,Changjiang River beach in Jiayu County,Hanbei River beach in Tianmen City,and Changshou River beach in Zhongxiang City,then the snail survey and wild feces detection were implemented in the selected environments. Re?sults There were O. hupensis snails,livestock,wild feces of cattle or sheep as well as positive cattle feces found in all the 4 environments,and the positive rate of schistosome miracidium incubation was 47.62%. Conclusion The schistosome miracidi?um positive rate of wild feces of cattle is high in the environments with snails in endemic areas of Hubei Province ,which has high risk for schistosomiasis transmission.
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Objective To understand the Oncomelania hupensis snail distribution in the working areas of Yangtze River hy?drologic agencies located in the middle and lower reaches of the Yangtze River in 2016,so as to provide the evidence for assess?ing the risk of schistosome infection of hydrological workers and establishing the control strategies. Methods The suspicious en?vironments with O. hupensis snails in the above working areas were selected as study areas,and the snail situation was surveyed by the system sampling method combined with the environmental sampling method. The survey data were collected and analyzed statistically. Results Totally 19 working areas from 17 hydrological agencies were selected as the investigation sites,among which,10 working areas from 9 agencies were found with O. hupensis snail distribution. The constituent ratio of the areas with snails reached to 38.81%of the investigation areas,the occurrence rate of frames with snails was 3.08%,and the average densi?ty of living snails was 0.07/0.1 m2. By comparison,the average density of living snails and occurrence rate of frames with snails in hydrological agencies under the jurisdiction of the Middle Reaches Administrative Bureau were the most serious among three administrative bureaus of the Yangtze River Water Resources Commission. Conclusions There are various degrees of O. hupen?sis breeding in the working areas of hydrological agencies located in the middle and lower reaches of the Yangtze River ,and the hydrological workers are facing with the risk of schistosome infection.
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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 understand the impact of Qionghai Lake wetland ecological protection construction on the preva?lence of schistosomiasis,so as to provide the evidence for formulating the strategies for schistosomiasis control and prevention. Methods A retrospective survey of the construction of Qionghai Lake wetland was performed,and eleven villages around the wetland were surveyed for schistosomiasis endemic situation. The influence of the wetland project on the schistosomiasis preva?lence and Oncomelania hupensis snail status were investigated. Results Before the construction of Qionghai Lake wetland,the snail elimination and extended chemotherapy for residents was performed. After the project was finished,the roads and ditches were hardened. From 2009 to 2014,the schistosome infection rate of residents declined from 0.37% to 0. No schistosome infect?ed snails were found and in recent 2 years,no snails were found. No mice were infected in the sentinel tests. Conclusions The construction of Qionghai Lake wetland effectively eliminates snails,and interrupts the transmission of schistosomiasis. Howev?er,the environment of the wetland is more suitable for snail breeding,and therefore,the surveillance still should be strength?ened.
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Objective To establish an Oncomelania hupensis snail database based on smartphone and Google Earth. Meth?ods The HEAD GPS software was loaded in the smartphone first. The GPS data of the snails were collected by the smartphone. The original data were exported to the computer with the format of KML/KMZ. Then the data were converted into Excel file for?mat by using some software. Finally the results based on laboratory were filled and the digital snail data were established. The data were converted into KML and then were showed by Google Earth visually. Results The snail data of a 5 hm2?beach along the Yangtze River were collected and the distribution of the snails based on Google Earth was obtained. The database of the snails was built. The query function was implemented about the number of the total snails the living snails and the schistosome infected snails of each survey frame. Conclusion The digital management of the snail data is realized by using the smartphone and Google Earth.
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Objective To evaluate the effect of ditching for drain on the control of the breed of Oncomelania hupensis snails in beaches of Dongting Lake. Methods From November,2009 to November,2012,an O. hupensis snail infested beach of the Yueyang jail and an O. hupensis snail infested beach of Junshan District were selected as research fields in the eastern Dongting Lake area,and the former,as the intervention field,was performed with the ditching for drain by excavators and the latter,as the control field,was not. Results Before the project implemented,the average soil moisture contents on the beaches in dry seasons of the two fields were both about 35.56%. After the project implemented,in the intervention field,the average soil mois?ture content was 26.53%which was significantly lower than that(35.56%)in the control field(F=6.53,P0.05),and after the project implemented(in 2012),no adult and young snails were found in the interventional field,but in the control field,the average densities of living snails and young snails were 29.37 snails/0.1 m2 and 213±108.45 snails/0.1 m2 respectively. Conclusion The intervention of ditching for drain can decrease the soil moisture contents quickly and change the ecological condition,therefore,can control the breed of O. hupensis snails in the beaches of Dongting Lake.
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Objective To provide the reference for schistosomiasis control through analyzing the changes of endemic status of schistosomiasis in China in recent years. Methods The annual data of schistosomiasis prevention and control from 2002 to 2012 were collected, and the descriptive analysis was conducted to describe the changes of schistosomiasis endemic status. Re?sults Sichuan, Yunan and Jiangxi provinces reached the criteria of transmission controlled from 2002 to 2010 while Hubei, Hu?nan, Jiangxi and Anhui provinces reached the criteria of infection controlled in 2008. The number of counties where the trans?mission of schistosomiasis was controlled decreased from 110 in 2002 to 80 in 2010. The numbers of estimated schistosomiasis cases and reported acute cases fell from 810.4 thousands and 913 in 2002 to 325.8 thousands and 43 in 2010, respectively, and they were reduced by 59.79%and 95.40%respectively. The number of infected bovine went down from 23 199 in 2002 to 7 173 in 2010, with a fall of 69.03%. However, the Oncomelania hupensis snails breeding areas kept in 3.7 to 3.8 billion m2 and among which, 125 million m2 areas were newly discovered in non?endemic areas during the nine years. In 2010, 90%of schistosomiasis cases, acute cases, infected bovine, and snail breeding areas were concentrated in 5 provinces, especially in the Dongting Lake and Poyang Lake areas and the regions along the Yangtze River. Conclusions The epidemic of schistosomiasis decreased sig?nificantly from 2002 to 2010. The lake regions are the key and tough areas for schistosomiasis prevention and control. To consoli?date the achievements, the surveillance and case management need to be strengthened as the extension of snail breeding areas and acute cases reported from other places becomes common.
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Objective To optimize the fermentation conditions of molluscicidal endophyte LL3026 from Buddleia lindleyana. Method The medium composition and cultivation conditions were optimized by orthogonal and single factor experiments. Re-sults The experiments showed that the conditions of initial pH 3,fermentation temperature 30℃,volume of liquid 100 ml(250 ml Erlenmeyer flask),and 3D-xylitol 0.5 g/L were optimum,and the molluscicidal activity of the fermentation filtrate reached 95%. After three hatches of cultivation,the predicted values were verified by validation experiments. Conclusion Endophyte LL3026 from Buddleia lindleyana has a good molluscicidal activity after the optimization.