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.

[Evaluation of implementation effect of schistosomiasis control program in Jiangsu Province from 2010 to 2015].

OBJECTIVE: To evaluate the actual effect of the schistosomiasis control program in Jiangsu Province from 2010 to 2015. METHODS: A total of 67 schistosomiasis-endemic counties in 10 cities were selected, and a combination of retrospective investigation and on-site investigation was adopted to collect and record the epidemic data of the counties from 2010 to 2015, and a retrospective survey database of epidemic situation was established. The effects of integrated control strategies with both Oncomelania hupensis snail control and infection source control were evaluated. RESULTS: From 2010 to 2015, 2 465 911 persons who lived in endemic areas were detected for schistosomiasis, with 16 974 positive cases of blood examinations, and 8 positive cases of fecal examinations. Totally 5 145 people with advanced schistosomiasis were treated and 40 460 people with the history of schistosome cercarial-infested water contact received the expanded chemotherapy. A total of 127 636 cattle raised in the endemic areas were detected, and 51 619 cattle (head-times) with the history of cercarial-infested water contact also received the expanded chemotherapy. The area with snails control by molluscicides was 18 604.84 hm2. By the end of 2015, schistosomeinfected snails had not been found and there was no zoological schistosome infection for 5 consecutive years, and in addition, there had been no acute schistosome-infected persons for 6 consecutive years in the whole province. The area with snails dropped to 1 977.18 hm2, with a decreasing rate of 55.24% compared with that in 2010. CONCLUSIONS: After the implementation of the plan for the prevention and control of schistosomiasis in Jiangsu Province (2010-2015), the prevention and control of schistosomiasis has achieved remarkable effects and realized the goal of the plan.

Effectiveness of snail control by immersion of molluscicides through tide diversion in marshlands: a field evaluation / 中国血吸虫病防治杂志

Objective To compare the effectiveness of snail control between immersion of molluscicides through tide diversion and mollusciciding by spraying in marshland areas. Methods Immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion and spraying 26% suspension concentrate of metaldehyde and niclosamide alone were employed for snail control in two neighboring snail-breeding marshlands, and snails were surveyed before and after mollusciciding. The mortality of snails and the density of living snails were estimated. Results The density of living snails reduced by 72.19% and 100.00% 1 and 2 years after immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion, and 5.93% and 18.15% 1 and 2 years after spraying 26% suspension concentrate of metaldehyde and niclosamide alone. Conclusion Immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion is significantly superior to spraying 26% suspension concentrate of metaldehyde and niclosamide along for snail control, and implementation of immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion for more than 2 successive years may achieve a higher snail control efficiency.

Effect and cost-effectiveness of three commonly used molluscicides in largescale field application / 中国血吸虫病防治杂志

Objective To evaluate the effect and cost-effectiveness of three commonly used molluscicides, 4% "Luo-wei" (tea-seed distilled saponins, TDS), 50% niclosamide ethanolamine salt wettable powder (NESWP), and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in large-scale field application, so as to provide the references for formulating the strategy of snail control. Methods The field test and parallel comparison were implemented. A marshland with Oncomelania hupensis snails of the Yangtze River was divided into 4 parts (10 hm2) for the research, and three of them were experimental areas while the last one was a blank control area. The experimental areas were sprayed with 4% "Luo-wei", 50% NESWP and 26% MNSC respectively for 3 times and the interval was 1 week. Seven days after each spraying the effect of snail control was investigated, and the costs of molluscicides, labor, transportation, fuel consumption and mechanical loss were recorded. The cost of each molluscicide, snail mortality, snail density, and the cost of increasing 1% of snail mortality per 100 m2 were analyzed and compared. Results After the first, second and third spraying, the corrected snail mortality rates were 67.34%, 76.55% and 84.60% respectively in the 4% "Luo-wei" group; the corrected snail mortality rates were 64.71%, 75.17% and 83.89% respectively in the 50% NESWP group; the corrected snail mortality rates were 66.55%, 76.27% and 86.67% respectively in the 26% MNSC group. There was no significant difference among the 3 groups in the snail mortality at the same spraying time (χ2 = 1.590, 0.571, 3.238, all P > 0.05) . In addition, along with the increase of the spraying times, the snail mortality of each group was increased significantly compared to that of the control group (χ2 = 79.333, 94.718, 117.020, all P < 0.01) . After the first, second and third spraying, the reduction rates of snail density were 69.82%–86.60% in the 4% "Luo-wei" group, 68.66%–86.55% in the 50% NESWP group, and 71.89%–88.87% in the 26% MNSC group respectively. The decreasing amplitude of the snail density was more than 85% in all the experimental areas after 3 rounds of spraying molluscicide. The snail control costs per 100 hm2 were 19.57, 11.97 Yuan and 10.47 Yuan in the 4% "Luo-wei" group, 50% NESWP group, and 26% MNSC group respectively. After the first, second and third spraying, the costs of increasing 1% of snail mortality per 100 m2 were 0.30, 2.08 Yuan and 2.38 Yuan in the 4% "Luo-wei" group, 0.20, 1.10 Yuan and 1.32 Yuan in the 50% NESWP group, and 0.17, 1.04 Yuan and 0.97 Yuan in the 26% MNSC group respectively, and the cost-effectiveness was the highest at the first spraying in all the three groups. Conclusions The effects of the three molluscicides for snail control are similar, but the efficacy of snail control is reduced as the spraying time increases.

Evaluation of implementation effect of schistosomiasis control program in Jiangsu Province from 2010 to 2015 / 中国血吸虫病防治杂志

Objective To evaluate the actual effect of the schistosomiasis control program in Jiangsu Province from 2010 to 2015. Methods A total of 67 schistosomiasis-endemic counties in 10 cities were selected, and a combination of retrospective investigation and on-site investigation was adopted to collect and record the epidemic data of the counties from 2010 to 2015, and a retrospective survey database of epidemic situation was established. The effects of integrated control strategies with both Oncomelania hupensis snail control and infection source control were evaluated. Results From 2010 to 2015, 2 465 911 persons who lived in endemic areas were detected for schistosomiasis, with 16 974 positive cases of blood examinations, and 8 positive cases of fecal examinations. Totally 5 145 people with advanced schistosomiasis were treated and 40 460 people with the history of schistosome cercarial-infested water contact received the expanded chemotherapy. A total of 127 636 cattle raised in the endemic areas were detected, and 51 619 cattle (head-times) with the history of cercarial-infested water contact also received the expanded chemotherapy. The area with snails control by molluscicides was 18 604.84 hm2. By the end of 2015, schistosomeinfected snails had not been found and there was no zoological schistosome infection for 5 consecutive years, and in addition, there had been no acute schistosome-infected persons for 6 consecutive years in the whole province. The area with snails dropped to 1 977.18 hm2, with a decreasing rate of 55.24% compared with that in 2010. Conclusion After the implementation of the plan for the prevention and control of schistosomiasis in Jiangsu Province (2010–2015), the prevention and control of schistosomiasis has achieved remarkable effects and realized the goal of the plan.

Effectiveness of snail control by immersion of molluscicides through tide diversion in marshlands: a field evaluation / 中国血吸虫病防治杂志

Objective To compare the effectiveness of snail control between immersion of molluscicides through tide diversion and mollusciciding by spraying in marshland areas. Methods Immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion and spraying 26% suspension concentrate of metaldehyde and niclosamide alone were employed for snail control in two neighboring snail-breeding marshlands, and snails were surveyed before and after mollusciciding. The mortality of snails and the density of living snails were estimated. Results The density of living snails reduced by 72.19% and 100.00% 1 and 2 years after immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion, and 5.93% and 18.15% 1 and 2 years after spraying 26% suspension concentrate of metaldehyde and niclosamide alone. Conclusion Immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion is significantly superior to spraying 26% suspension concentrate of metaldehyde and niclosamide along for snail control, and implementation of immersion of 26% suspension concentrate of metaldehyde and niclosamide through tide diversion for more than 2 successive years may achieve a higher snail control efficiency.

[Effect and cost-effectiveness of three commonly used molluscicides in largescale field application].

OBJECTIVE: To evaluate the effect and cost-effectiveness of three commonly used molluscicides, 4% "Luo-wei" (tea-seed distilled saponins, TDS), 50% niclosamide ethanolamine salt wettable powder (NESWP), and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in large-scale field application, so as to provide the references for formulating the strategy of snail control. METHODS: The field test and parallel comparison were implemented. A marshland with Oncomelania hupensis snails of the Yangtze River was divided into 4 parts (10 hm2) for the research, and three of them were experimental areas while the last one was a blank control area. The experimental areas were sprayed with 4% "Luo-wei", 50% NESWP and 26% MNSC respectively for 3 times and the interval was 1 week. Seven days after each spraying the effect of snail control was investigated, and the costs of molluscicides, labor, transportation, fuel consumption and mechanical loss were recorded. The cost of each molluscicide, snail mortality, snail density, and the cost of increasing 1% of snail mortality per 100 m2 were analyzed and compared. RESULTS: After the first, second and third spraying, the corrected snail mortality rates were 67.34%, 76.55% and 84.60% respectively in the 4% "Luo-wei" group; the corrected snail mortality rates were 64.71%, 75.17% and 83.89% respectively in the 50% NESWP group; the corrected snail mortality rates were 66.55%, 76.27% and 86.67% respectively in the 26% MNSC group. There was no significant difference among the 3 groups in the snail mortality at the same spraying time (χ2 = 1.590, 0.571, 3.238, all P > 0.05) . In addition, along with the increase of the spraying times, the snail mortality of each group was increased significantly compared to that of the control group (χ2 = 79.333, 94.718, 117.020, all P < 0.01) . After the first, second and third spraying, the reduction rates of snail density were 69.82%-86.60% in the 4% "Luo-wei" group, 68.66%-86.55% in the 50% NESWP group, and 71.89%-88.87% in the 26% MNSC group respectively. The decreasing amplitude of the snail density was more than 85% in all the experimental areas after 3 rounds of spraying molluscicide. The snail control costs per 100 hm2 were 19.57, 11.97 Yuan and 10.47 Yuan in the 4% "Luo-wei" group, 50% NESWP group, and 26% MNSC group respectively. After the first, second and third spraying, the costs of increasing 1% of snail mortality per 100 m2 were 0.30, 2.08 Yuan and 2.38 Yuan in the 4% "Luo-wei" group, 0.20, 1.10 Yuan and 1.32 Yuan in the 50% NESWP group, and 0.17, 1.04 Yuan and 0.97 Yuan in the 26% MNSC group respectively, and the cost-effectiveness was the highest at the first spraying in all the three groups. CONCLUSIONS: The effects of the three molluscicides for snail control are similar, but the efficacy of snail control is reduced as the spraying time increases.

Effect and cost-effectiveness of three commonly used molluscicides in largescale field application / 中国血吸虫病防治杂志

Objective To evaluate the effect and cost-effectiveness of three commonly used molluscicides, 4% "Luo-wei" (tea-seed distilled saponins, TDS), 50% niclosamide ethanolamine salt wettable powder (NESWP), and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in large-scale field application, so as to provide the references for formulating the strategy of snail control. Methods The field test and parallel comparison were implemented. A marshland with Oncomelania hupensis snails of the Yangtze River was divided into 4 parts (10 hm2) for the research, and three of them were experimental areas while the last one was a blank control area. The experimental areas were sprayed with 4% "Luo-wei", 50% NESWP and 26% MNSC respectively for 3 times and the interval was 1 week. Seven days after each spraying the effect of snail control was investigated, and the costs of molluscicides, labor, transportation, fuel consumption and mechanical loss were recorded. The cost of each molluscicide, snail mortality, snail density, and the cost of increasing 1% of snail mortality per 100 m2 were analyzed and compared. Results After the first, second and third spraying, the corrected snail mortality rates were 67.34%, 76.55% and 84.60% respectively in the 4% "Luo-wei" group; the corrected snail mortality rates were 64.71%, 75.17% and 83.89% respectively in the 50% NESWP group; the corrected snail mortality rates were 66.55%, 76.27% and 86.67% respectively in the 26% MNSC group. There was no significant difference among the 3 groups in the snail mortality at the same spraying time (χ2 = 1.590, 0.571, 3.238, all P > 0.05) . In addition, along with the increase of the spraying times, the snail mortality of each group was increased significantly compared to that of the control group (χ2 = 79.333, 94.718, 117.020, all P < 0.01) . After the first, second and third spraying, the reduction rates of snail density were 69.82%–86.60% in the 4% "Luo-wei" group, 68.66%–86.55% in the 50% NESWP group, and 71.89%–88.87% in the 26% MNSC group respectively. The decreasing amplitude of the snail density was more than 85% in all the experimental areas after 3 rounds of spraying molluscicide. The snail control costs per 100 hm2 were 19.57, 11.97 Yuan and 10.47 Yuan in the 4% "Luo-wei" group, 50% NESWP group, and 26% MNSC group respectively. After the first, second and third spraying, the costs of increasing 1% of snail mortality per 100 m2 were 0.30, 2.08 Yuan and 2.38 Yuan in the 4% "Luo-wei" group, 0.20, 1.10 Yuan and 1.32 Yuan in the 50% NESWP group, and 0.17, 1.04 Yuan and 0.97 Yuan in the 26% MNSC group respectively, and the cost-effectiveness was the highest at the first spraying in all the three groups. Conclusions The effects of the three molluscicides for snail control are similar, but the efficacy of snail control is reduced as the spraying time increases.

Evaluation of implementation effect of schistosomiasis control program in Jiangsu Province from 2010 to 2015 / 中国血吸虫病防治杂志

Objective To evaluate the actual effect of the schistosomiasis control program in Jiangsu Province from 2010 to 2015. Methods A total of 67 schistosomiasis-endemic counties in 10 cities were selected, and a combination of retrospective investigation and on-site investigation was adopted to collect and record the epidemic data of the counties from 2010 to 2015, and a retrospective survey database of epidemic situation was established. The effects of integrated control strategies with both Oncomelania hupensis snail control and infection source control were evaluated. Results From 2010 to 2015, 2 465 911 persons who lived in endemic areas were detected for schistosomiasis, with 16 974 positive cases of blood examinations, and 8 positive cases of fecal examinations. Totally 5 145 people with advanced schistosomiasis were treated and 40 460 people with the history of schistosome cercarial-infested water contact received the expanded chemotherapy. A total of 127 636 cattle raised in the endemic areas were detected, and 51 619 cattle (head-times) with the history of cercarial-infested water contact also received the expanded chemotherapy. The area with snails control by molluscicides was 18 604.84 hm2. By the end of 2015, schistosomeinfected snails had not been found and there was no zoological schistosome infection for 5 consecutive years, and in addition, there had been no acute schistosome-infected persons for 6 consecutive years in the whole province. The area with snails dropped to 1 977.18 hm2, with a decreasing rate of 55.24% compared with that in 2010. Conclusion After the implementation of the plan for the prevention and control of schistosomiasis in Jiangsu Province (2010–2015), the prevention and control of schistosomiasis has achieved remarkable effects and realized the goal of the plan.

[Surveillance and risk assessment system of schistosomiasis in Jiangsu Province â ¢ Risk of schistosomiasis transmission in the area along the Yangtze River in Yangzhou City].

OBJECTIVE: To evaluate the potential risk of schistosomiasis transmission in the area along the Yangtze River in Yangzhou City, so as to provide evidences for establishing a post-transmission surveillance system for schistosomiasis in marshland regions. METHODS: The water infectivity, floating boatmen and fishermen infection, reservoir host infection and wild feces contamination were investigated in five districts/counties along the Yangtze River in Yangzhou City, including Guangling, Hanjiang, Jiangdu, Yizheng and Development Zone, and the transmission factors and risky characteristics were assessed after interruption of schistosomiasis transmission in marshland regions. RESULTS: A total of 15 key water regions were identified in the area along the Yangtze River in Yangzhou City in 2015. A total of 1 500 sentinel mice were placed, after breeding, their overall survival rate was 99.33%; 1 490 were dissected, with no schistosome infection. Of the 5 576 floating boatmen and fishermen examined, no schistosome infection was observed, and among the 3 566 domestic animals (including 171 cattle, 1 895 sheep and 1 500 pigs), no infections were detected. During the period between January and March, 2016, there were 3 200 mouse traps placed on 8 marshlands, and 62 wild mice were captured from 6 marshlands, with a capture rate of 1.94%, and no schistosomeinfected wild mice were seen. In addition, there were 35 pieces of fresh wild feces captured from 7 marshlands, including 11 pieces of bovine feces (31.43%), 17 pieces of sheep feces (48.57%), 2 pieces of dog feces (5.71%) and 5 pieces of other feces (14.29%), and no infections were detected. CONCLUSIONS: There is a low risk of schistosomiasis transmission in the area along the Yangtze River in Yangzhou City. However, the contamination of feces from bovine and sheep that are freely pastured on marshlands is a big threat to schistosomiasis control.

[Study on schistosomiasis control measures in mobile boat fishermen. III. Construction and application of regional joint mechanism for schistosomiasis examination and treatment in boatmen].

OBJECTIVE: To construct the regional joint mechanism for schistosomiasis examination and treatment and the examination protocol among mobile boatmen, so as to provide effective measures for control of mobile infectious sources of schistosomiasis in the Yangtze River basin. METHODS: According to the characteristics of the cargo frequent mobility of ships with fixed anchor points, the health, maritime and transport sections were jointly cooperated to set up sites for schistosomiasis examination and treatment in ship locks, wharfs and harbors. The infection of schistosomiasis was detected by means of rapid immunological screening and stool examination, and the regional joint mechanism was constructed. The sero-positives were traced for further parasitological examinations and treatment by using the regional joint network for schistosomiasis examination and treatment. The schistosome infections in boatmen were analyzed and compared between different examination and treatment sites and among different navigation coverage. RESULTS: A total of 16 sites for examination and treatment of schistosomiasis, including 5 fixed sites and 11 mobile sites, were set up in 12 townships of 6 districts (counties) of Yangzhou City. During a period between June and August, the examination of schistosomiasis was conducted in 40 sites, and of the 1 225 boatmen from 967 boats detected, 19 cases were sero-positive, with a positive rate of 1.55%. Among the 14 sero-positives examined, no stool positive patients were found. Among the 1 225 boatmen detected, 820 were from fixed sites and 405 from mobile sites, and 4 and 15 cases were found, respectively, with positive rates of 0.49% and 3.70%, respectively, and the sero-positive rate was higher in mobile sites and that in fixed sites. A total of 898 boatmen from the Yangtze River basin and 305 from the local inland rivers were examined, and 3 and 16 sero-positive cases were detected, respectively, with positive rates of 0.33% and 5.25%, respectively, and the sero-positive rate was significantly higher in the boatmen from the local inland rivers than that from the Yangtze River basin. CONCLUSION: Regional joint mechanism is an effective strategy for examination and treatment of schistosomiasis among mobile boatmen, which provides a new approach to control mobile infectious sources of schistosomiasis in the Yangtze River basin.