[Strategy and effect of Oncomelania hupensis snail control in inside-embankment areas in Junshan District, Hunan Province from 1998 to 2017].

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 prevention 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 1 496.66 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 prevention and control was 398.857 million RMB in Junshan District, including molluscicide (81.770 9 million RMB) and environment reform (213.5 million RMB) respectively. CONCLUSIONS: 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.

Strategy and effect of Oncomelania hupensis snail control in inside-embank-ment areas in Junshan District ,Hunan Province from 1998 to 2017 / 中国血吸虫病防治杂志

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.

Classification and grading of environments with Oncomelania hupensis snails inside embankment of marshland and lake areas / 中国血吸虫病防治杂志

Objective To classify and grade the environments with Oncomelania hupensis snails inside embankment in marsh-land and lake areas,so as to improve the work efficiency and realize the systematic management. Methods The schistosomiasis endemic area Liaodi and Xiongdi villages in Jiangling County,Hubei Province were selected as the experiment villages,and the environments with snails in the two villages were divided into sections with a length of 500m,then the snail situation were sur-veyed by the systematic sampling method with 10m and 50m a frame respectively. The environments were classified according to the discovery of infected snails and wild fecal contamination,and the numbers of sites with snails and their areas in different class-es were recorded. Meanwhile,the data of sites with infected snails in Jingzhou City during the recent 5 years were collected and graded according to the average density of snails,so as to discuss the correlativity between the grades of environments with snails and the numbers of sites with infected snails and the occurrence rate of frames with snails. Results There were 1 967 sites with in-fected snails in Jingzhou City during the recent 5 years,and there was a positive correlation between the grades of environments with snails and the occurrence rate of frames with snails(rs=0.77,P0.05),but the time-consuming of the former was 3 times of the latter. Conclusions The classification and grading of the environments with snails inside embankment in marshland and lake areas can master the key point of the snail survey. The subsection and setting frames at a suitable distance can save time and manpower,improve work efficiency,as well as understand the distribution of snail status of the environment with snails,which can realize the sort management of the snail envi-ronments inside embankment.