[Further study on possibility of diffusion of Oncomelania hupensis with water in river channels of the east route of South-to-North Water Diversion Project].

OBJECTIVE: To study the drifting law of floats and potential risks of Oncomelania hupensis diffusion in the water diversion rivers of the east route of South-to-North Water Diversion Project. METHODS: The O. hupensis snails in the river channels were monitored by the salvage method and snail luring method with rice straw curtains, and the diffusion possibility of snails along with water was assessed through the drift test of floats with GPS. RESULTS: In the flood seasons from 2006 to 2013, totally 8 338.0 kg of floats were salvaged, and 2 100 rice straw curtains were put into water in the Li Canal and Jinbao shipping channel, but no Oncomelania snails were found. The drift test of floats with GPS before water diversion showed that the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.56 - 0.60 m/s, and the average drift distances each time were 999.70 - 1 995.50 m in the Gaoshui River section, while there were no obvious drift in Jinbao shipping channel section. During the water diversion period, the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.35 - 0.41m/s, and the average drift distances each time were 1 248.06 -1 289.44 m in the Gaoshui River, while in Jinbao shipping channel section, the flow velocity on water surface was 0.28 m/s, the average drift velocity of the floats was 0.25 - 0.27 m/s, and the average drift distances each time were 477.76 - 496.38 m. The drift test showed that the floats gradually closed to the river bank as affected by water flow, wind direction and ship waves, when blocked by the reeds, water plants or other obstacles, and they would stopped and could not continue to drift without outside help. CONCLUSIONS: There are no Oncomelania snails found in the river channels of the east route of South-to-North Water Diversion Project. The drifting distance of the floating debris along with the water is restricted by the flow rate and shore environment.

[Establishment and application of imported falciparum malaria control system in Yangzhou City].

To aim at the characteristics of epidemic situation that the imported falciparum malaria cases increased year by year in Yangzhou City, an imported falciparum malaria control system was established. This control system was based on enhancing the management of returned labor service export persons from falciparum malaria endemic areas, the active medical remind service, the diagnostic capability and health education, and the cooperation of medical personnel and patients, and also avoiding diagnosis delay and misdiagnosis and promoting the treatment in time so as to decrease the serious patients and prevent them from death. After the application of the control system, there were 164 imported falciparum malaria cases from the returned persons of labor service export. The time from the attack of the disease to the diagnosis confirmed decreased from 6.8 days before the application of the system to 2.7 days after the application, and the rate of serious patients was 1.8% and there were no death cases.

[Effect of sand buried on elimination of Oncomelania hupensis snails in marshland along Yangtze River in Jiangdu District, Jiangsu Province].

OBJECTIVE: To evaluate the effect of sand buried on the elimination of Oncomelania snails in the marshland along the Yangtze River downstream. METHODS: The areas along the Yangtze River were chosen as the investigated objects in Jiangdu District, Jiangsu Province. The datum review and field investigations were used to observe the change of snail area after the sand buried. RESULTS: There were 11 sand buried projects along the Yangtze River in Jiangdu District, Jiangsu Province. The snail areas decreased by 93.73% after the sand buried. CONCLUSION: The sand buried is an effective method of snail control in the marshland along the Yangtze River. This method can be combined with economic construction and development projects for popularization and application.

[Technology of preventing oncomelania snail diffusion in east route of South-to-North Water Diversion Project II. Effect of sand buried and reed protection on snail control in area of water source].

OBJECTIVE: To evaluate the effect of sand buried and reed protection on Oncomelania snail control in the area of water source of the east route of South-to-North Water Diversion Project. METHODS: The Oncomelania snail eggs were counted after the snails raised seven days in the sand of different contents in the spawning period. The survival of the snails was observed when the snails were raised on the sand surface in the laboratory. The change of the densities of living snails and reed growth were observed in the area of water source. RESULTS: The snails did not lay eggs in the pure sand environment. There was a negative correlation between the number of snail eggs and the content of sand (r = -0.965, P = 0.008). The mortality rates of the snails were increasing with the increase of the time in the sand environment. The mortality rates of the snails were 96.00% and 100% when the snails were raised 3 months and 6 months around 25 degrees C respectively. The field test showed that the snails were not discovered after the sand buried, the second spring, after the flood season, and the third spring. However, the density of living snails of the control group dropped by 93.65% 2 weeks after using molluscicide, but increased by 100% and kept in 0.37 snails/0.1 m2 after the flood season and the third year spring, respectively. The reed growth was good in the second spring after the sand buried. CONCLUSIONS: The sand environment is unfavorable for laying eggs and survival of the snails. The sand buried method has the effects of snail control and reed protection. In addition, the method could also prevent the snail spread in the flood season.

[Epidemic situation and prevention and control countermeasures of imported falciparum malaria in Jiangdu District, Yangzhou City].

OBJECTIVE: To explore the feasible prevention and control measures for imported falciparum malaria. METHODS: The epidemic situation of imported falciparum malaria and status of labor export were investigated by using the epidemic statistical method, epidemiological survey and follow-up survey. RESULTS: There were 46 direct network reported cases of imported falciparum malaria in Jiangdu District in 2011, and they were all export laborers to Africa, being aged from 30-49 years, Totally 28 patients of them had the history of disease in foreign countries, and 29 cases were in the same labor export services company. A total of 444 migrant labors were investigated and 24 patients were diagnosed falciparum malaria. CONCLUSION: In order to prevent and control imported falciparum malaria, we should strengthen the standard management of labor export services market and health education.

[Exploration of model of Oncomelania snail survey post-transmission control in Jiangdu City].

OBJECTIVE: To explore the model of Oncomelania snail survey in inland areas, so as to reduce the burden of farmers as well as to improve the quality of snail survey. METHODS: A database of environment in snail survey was established, and specialized personnel were organized at town level. The general survey combined with survey in turn was used. RESULTS: After the improvement of the survey model, the personnel numbers and amounts of labor used, especially the cost afforded at village level decreased significantly, without any influence on the quality of snail survey. CONCLUSIONS: The improvement of snail survey model can enhance the efficiency and quality of survey, and can reduce the burden of farmers, but careful organization, strengthened management, and standardized operations are needed in the procedure.

[Impact of simulation operation high water level on Oncomelania hupensis natural growth in water diversion rivers of east route of South-to-North water Diversion Project].

OBJECTIVE: To verify the impact of operation high water level on Oncomelania hupensis natural growth in the water diversion rivers of the east route of South-to-North Water Diversion Project. METHODS: The data of the daily mean water level were investigated in the stilling pool of Jiangdu Pumping Station during the water diversion under the emergency anti-drought, and the water level data of the previous year served as the control. The dynamic of natural growth of O. hupensis snails was observed before and after the high water level in the beach wetlands of the stilling pool of Jiangdu Pumping Station. The water level of emergency anti-drought was as simulation operation water level of the east route of South-to-North Water Diversion Project in the stilling pool, and then the effects of operation water level on O. hupensis natural growth in the water diversion rivers of the east route of South-to-North Water Diversion Project were studied. RESULTS: The altitude of the beach wetlands was 6.4 to 7.2 meters in the stilling pool of Jiangdu Pumping Station. The water diversion was 255 days continuously and the pumped water was 6.235 billion cubic meters in the Jiangdu Pumping Station from November 2010 to July 2011. There were 216, 136 days and 39 days when daily mean water level were more than or equal to 7.2, 7.6 and 8.0 meters during the water diversion, respectively. The snail densities were 0.856 snails/0.1m2 and 0.0153 snails/0.1m2, respectively, before and after the No.3 beach wetlands flooded in the stilling pool of Jiangdu Pumping Station. The densities of living snails decreased by 98.21%, and there was no any progeny of snail. The snails were not detected in other environment of the stilling pool. CONCLUSION: The operation high water level can effectively restrain snail breeding in the water diversion rivers of the east route of South-to-North Water Diversion Project.