[Molluscicidal effects of 3 molluscicides by spraying and poudrage methods in dry season].

OBJECTIVE: To evaluate the effects of 3 molluscicides namely 5% niclosamide ethanolamine granules, 4% "Luowei" (Tea-seed distilled saponins, TDS) and 50% wettable powder of niclosamide ethanolamine salt (WPN) by spraying and poudrage methods in marshland and lake regions in dry season. METHODS: An environment with a high snail density was chosen as the experimental field, then the spraying and poudrage experiments were carried out in the field to assess the molluscicidal effects of 5% niclosamide ethanolamine granules, TDS and WPN delivered by spraying and poudrage methods with a concentration of 30, 6 and 2 g/m2, respectively, and the molluscicidal effects of the 3 drugs by the two methods were evaluated and compared in different time. RESULTS: After the delivery for 15 d, the adjusted snail death rates of the 5% niclosamide ethanolamine granules, TDS and WPN in the spraying experiment were 79.00%, 82.29% and 84.83%, respectively, and those in the poudrage experiments were 97.42%, 95.27% and 96.62%, respectively. CONCLUSION: The molluscicidal effect of poudrage method is better than the spraying method, and the former is worthy of further extension and application in the marshland in dry season.

[Molluscicidal effect of plastic film mulch covering method].

OBJECTIVE: To evaluate the molluscicidal effect of the plastic film mulch covering method. METHODS: In the barren land with a lot of Oncomelania hupensis snails, 3 experimental groups were set up, in which respectively using 3 different methods: a simple plastic film mulch covering method, film assisted with ammonium bicarbonate, and film assisted with amine molluscicide. In the canals, two experimental groups were set up, in which respectively using 2 different methods: simple plastic film mulch covering method and film assisted with ammonium bicarbonate. In above-mentioned areas, obstacles were cleared artificially. In each experiment group, 4 observation spots were set up, and 100 living snails were pot in each spot, and then, the plastic film mulch was evenly covered. The status of the snails was observed 3, 7, 15 and 30 days after the intervention. RESULTS: In the barren land, the snail death rates of the simple plastic film group were 20.77% and 96.92% 15 days and 30 days after the intervention, respectively. The snail death rate of the film assisted with amine molluscicide group was 80.46% 3 days after the intervention. In all the experiment groups, the snail death rates were from 96.92 to 100% 30 days after the intervention. CONCLUSION: The plastic film mulch covering method has a great molluscicide effect in the hill subtype and water network type of schistosomiasis epidemic areas.

[Surveillance of schistosomiasis in Caohui Village, Yangxin County, 2005-2010].

The surveillance of schistosomiasis in a national schistosomiasis surveillance site, Caohui Village, Yangxin County, 2005 - 2010 showed that the infection rates of residents and livestock decreased from 4.56% and 28.33% to 1.19% and 1.67%, respectively. However, the endemic situation was still of instability. Therefore, we should strengthen the comprehensive control measures including the control of infectious sources in the light of local conditions to control the schistosomiasis endemic situation.