| Objective 1. To grasp the fluctuation trend of main biological vectors, and analyze the impact of the water storage and project construction on the biological vectors. 2. Analyze the epidemic of biological vector related diseases in animal hosts and people, so we can predict the prevalence trend of biological vector related diseases. 3. Evaluate the impact of Three Gorges Project on the epidemic of biological vector related diseases in the Three Gorges Dam Area.Methods 1. In field survey, we applied night trapping method to capture rodents and electric mosquito killers to capture mosquitoes.2. In laboratory animal host detection, rodents` epidemic hemorrhagic fever(EHF) antigen was detected by direct immunofluorescence assay, and antibody was detected by indirect immunofluorescence assay. The kidneys of each captured rodent were inoculated in Korthof medium for Leptospirosis culturing. Metacercarias in stream crabs were detected by double-tubes anatomical lens. About seroepidemiology, we used Enzyme-linked Immunosorbent Assay (ELISA) for human serum EHF and paragonimus IgG test. Leptospira antibodies was tested by microscopic agglutination test (MAT).3. We used Excel 2003 to establish the data sets, and completed the statistical analysis with a popular software named SPSS13.0.Results 1. From 2006 to 2008, rodent density had varied as a reversed"V", and reached its peak in September 2007. The rodent density of upstream was higher than the density of downstream. Indoor rodent density (9.82%-17.33%) was higher than outdoor rodent density (1.42%-5.96%). Rattoides and Mus musculus were the indoor dominant species. Apodemus agrarius and Rattus norvegicus were the indoor dominant species. Stream crabs density was at a decline trend during the survey. Sinopotamon xingshanense and Sinopotamon denticulatum were the dominant species. Mosquito density was little higher in 2007 than that in 2006, and the dominant species were Culex quinquefasciatus and Armigeres harassment, Anopheles sinensis only accounted for 0.55%.2. From 2006 to 2008, EHF antigen and antibody of rodent were in a rising trend, there was no infection different among rodent species. People`s latent infection rate in upstream was higher than that in downstream, and pupil was the highest infection rate population.3. From 2006 to 2008, there was no significant changes about rodent leptospira infection rate. Outdoor rodent infection rate was higher than that of indoor rodent. Apodemus agrarius got the highest infection rate. In dam area, health people`s latent leptospira infection rate in 2007 was higher than that of 2006, and people`s latent infection rate in upstream was higher than that in downstream, famers got the highest infection rate.4. In dam area, stream crabs` metacercarias infection rate was highest in 2006, and the species of highest infection rate was Tenuilapotamon joshuiense. Health people`s latent infection rate in 2007 was significant higher than that in 2006, and people` infection rate in upstream was higher than that in downstream, pupils got the highest latent infection rate. Conclusion 1. Because of the reservoir construction and the water storage, the structure and density of main biological vectors had been changed greatly.2. Rodent density, especially indoor rodent density had increased, and rodent EHF infection rate had been in a rising rate, at the same time, people in dam area were at a low immune level, so the people were may at a high risk of epidemic of EHF.3. In dam area, rodents got a high level of leptospira infection rate, people were at a low immune level and got higher contact rate with animal host, so the hazard of the epidemic of leptospirosis is big. In future, it is necessary for outdoor workers to protect themselves better.4. In dam area, stream crabs density was at a decline trend, and stream crabs` metacercarias infection rate was at a low level, so it is less likely for paragonimiasis to epidemic or outbreak. |
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