ABSTRACT
Objective To evaluate the effect of the water conservancy schistosomiasis control projects combined with mollus-cicide to control Oncomelania hupensis snails in the rivers connecting with the Yangtze River. Methods The water conservancy schistosomiasis control projects of Zhujiashan River,Qili River and Gaowang River were chosen as the study objects in Pukou District,Nanjing City. The data review method and field investigation were used to evaluate the effect of the water conservancy schistosomiasis control projects combined with molluscicide to control O. hupensis snails. Results After the projects of the wa-ter level control and concrete slope protection and mollusciciding were implemented,the snails in the project river sections were completely eliminated. The snail diffusion did not happen in the inland irrigation area too. In the outside of the river beach , though the snails still existed,the snail densities plunged below 1.0 snail per 1.0 m2. Conclusion The comprehensive mea-sures of the combination of water level control,concrete slope protection and mollusciciding can effectively control and eliminate the snails,and prevent the snails from spreading.
ABSTRACT
The elimination of Oncomelania hupensis snails is important to schistosomiasis control. Recently,the application of molluscicidal organisms is considered as a safe and efficient method for snail elimination. In order to provide scientific evi?dences for effective control of O. hupensis and schistosomiasis,this paper summarizes the researches of molluscicidal microor?ganisms against O. hupensis.
ABSTRACT
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.
ABSTRACT
A comprehensive strategy for snail control, including environmental modification and mollusciciding, was implemented in Ya-he River, Changsha County of Hunan Province from 2003 to 2004. The snail status declined significantly in 2005 and 2006, and no snailswere found since 2007. It is indicated that the environmental modification combined with mollusciciding is an effective approach for snailcontrol so as to control the transmission of schistosomiasis.