ABSTRACT
Objective To evaluate the molluscicidal effect of Rongbao in schistosomiasis endemic areas in Mianyang City. Methods Three Oncomelania hupensis snail habitats with the similar snail status were selected and sprayed with Rongbao,ni-closamide,and fresh water,respectively. Then the snail status in the three fields was surveyed before the spraying and 7,15,30 and 60 days after the spraying,and the molluscicidal effects of different molluscicides were compared. Results The reducing rates of densities of living snails in the field sprayed with Rongbao were 94.4%,95.9%,98.2%and 98.8%,7,15,30 and 60 days after the spraying,respectively. The reducing rates of the densities of living snails in the other field sprayed with niclosamide were 94.0%,94.0%,89.9%and 92.2%in above-mentioned days,respectively. In the 30 days and 60 days after the spraying,the reducing rates of densities of living snails in the field sprayed with Rongbao were significantly higher than those sprayed with ni-closamide(χ230 d=8.18,χ260 d=3.97,Both P<0.05). Conclusion The short-term molluscicidal effect of Rongbao is similar to that of niclosamide,but the long-term effect of Rongbao is better than that of niclosamide.
ABSTRACT
Objective To compare the field molluscicidal effects of 25%suspension concentrate of nielosamide ethanolamine salt(SCNE),50% wettable powder of niclosamide ethanolamine salt(WPN),40% META-Li and 50% Rongbao powder,so as to provide scientific basis for choosing the safe and highly effective molluscicide in field.Methods Four snail habitats with the similar snail status were selected and sprayed with the four molluscicides mentioned above,respectively.Then the snail status in the four fields was surveyed 3,7 and 17 d after the spraying and the moiluscicidal effects of difierent molluscieides were cornpared.Results The corrected mortalities of snails in the field sprayed with SCNE 3,7 and 17 d afterthe spraying were the hiishest among the four fields,with the rates of 93.13%,91.85% and 85.28%,respectively.Conclusion SCNE has a high molluseieidal effect in the field and can be further used in snail-infested areas.
ABSTRACT
Objective To observe the effects of calcium cyanamide (Rongbao) on the histological and morphological changes of Oncomelania hupensis snails in order to explore its molluscicidal mechanisms.Methods The serial snails' slides were fixed after soaking in a concentration of Rongbao leached liquor at different time.The histological and morphological changes of the snails were compared among these slides.Results After soaking in the Rongbao leached liquor for 48 h,the mantle epithelia,respiratory epithelia of the gill,liver cells,and muscle cells of gastropods were injured seriously,which resulted in the death of the snails directly.The death rates of the snails were 96.70% and 100% after soaking in the Rongbao leached liquor for 48 h and 72 h,respectively.Conclusion Rongbao is an effective molluscicide by damaging the several snail tissues.