[Molluscicidal effect of simple black film mulching in mountainous areas of Yunnan Province].

OBJECTIVE: To evaluate the molluscicidal effect of black plastic mulching in mountainous areas of Yunnan Province. METHODS: In Leqiu Village, Nanjian County, Yunnan Province, the terraced fields with Oncomelania hupensis snails were divided into A, B, C, D, E groups, and of which, A, B, C, D groups, as the experimental groups, were administered with simple black plastic mulching for 30 days, 60 days, 90 days and 120 days respectively; Group E, as the control group, was administered with 50% niclosamide ethanolamine salt wettable powder spraying. RESULTS: In Group C and D (simple black film mulching for 90 days and 120 days), no snails were found after the administration, the average density of living snails decreased by 100%, and the cost of one year was similar to that of the control group. CONCLUSION: The molluscicidal effect of black plastic mulching is good in mountainous areas.

[Investigation on infection sources of schistosomiasis in mountainous regions, Nanjian County, Yunnan Province].

OBJECTIVE: To understand the types of schisotsome infection sources and their roles in schistosomiasis transmission in mountainous endemic regions in Yunnan Province, so as to provide the evidence for implementing the comprehensive control measures based on infection source control. METHODS: Two villages of typical mountainous regions in Nanjian County were chosen for field investigation. The Oncomelania hupensis snail status was surveyed by the methods of systematic and environmental sampling. The infections of schistosomiasis were surveyed in residents with the indirect haemagglutination and the hatching method, in livestock with the hatching method and in wild animals with the anatomical method and the hatching method. The distribution and pollution status of wild faeces were investigated in the snail environments nearby villages or with livestock frequent activities. The positives of schistosomiasis in wild faeces were tested with the hatching method. The pollution index of wild feces was calculated. RESULTS: A total of 533.56 hm2 were investigated in two villages, and the area with snails was 16.52 hm2. The rate of frame with snails was 1.03%, the average density of snails was 0.07 snails/0.1 m2, and no positive snails were found. The positive rate of blood examinations of population was 1.61%, but no persons were positive with the hatching method. The infection rates were 0.90%, and 0.62% in cattle and equus, respectively, and there were no positives in other livestock. Totally 472 piles of wild feces of 6 species (human, cattle, equus, goat, pig and dog) distributed in the investigation areas, and among them, the densities of wild feces of cattle, equus, and dog were 7.2, 4.3 piles/hm2, and 2.1 piles/hm2 respectively, being relatively higher than others. The hatching positive rates of wild faeces of cattle, equus, and dog were 2.27% (3/132), 2.63% (2/76), and 3.70% (1/27), respectively. The relative pollution indexes of wild faeces of cattle, equus, and dog were 80.68%, 15.89%, and 3.43%, respectively. CONCLUSIONS: After schistosomiasis transmission is controlled, the potential epidemic factors still remain in the mountainous endemic regions of schistosomiasis in Yunnan Province. The cattle are still the most infection source of schistosomiasis, but equus and dog as infection sources should be not neglected. We should extend the investigation and monitor scope of the infection sources, and carry out scientific and feasible control technique and management measures.

[Effect of snail control of niclosamide by soil mixing and spraying methods in high dam of terrace].

The snail control efffect of niclosamide by soil mixing and spraying method were compared, and the results showed that the effects of the two methods were similar. Though there was difficulties in getting soil and mixing durg with soil, and the cost was high, the effect of soil mixing method in some special environment such as stone ditches and terraces.

[Effect of comprehensive control project on schistosomiasis in Nanjian county].

The comprehensive control project for schistosomiasis was implemented in Nanjian County from 2004 to 2008. After the implementation of the control project, the infection rates of population and livestock decreased by 94.39% and 83.29% in 2008, respectively, with both infection rates less than 1%, no acute schistosomiasis cases had been found since 2005. Snail areas decreased by 70.01%, no infected snails had been found since 2007. Through the implementation of the comprehensive control project, schistosomiasis had been effectively controlled in Nanjian County.