Epidemiological investigation of host and focus of natural infection on hemorrhagic fever with renal syndrome in migration areas of the Yangtze River Three-Gorge Reservoir Chongqing region / 第三军医大学学报

ABSTRACT

Objective　To ascertain the natural infection rate of hemorrhagic fever with renal syndrome virus (HFRSV) among its hosts and the type of the natural foci for providing some baseline data for the immigrant health and epidemic prevention of the Three-Gorge region. Methods　Epidemiological survey on the field was performed including epidemiological data collection, ecology of rodents and pathogen detection. HFRS virus antigen of hosts were detected by the direct immunofluorescent assay (DIFA) technique and determination of HFRSV-RNA by ISH were carried out from HFRSV-Ag-positive animals. Results　HFRSV-Ag-positive animals were found in 5 migration areas ie Baitao Town of Fuling Section, Wansheng Village of Fengjie County and Dachang Town of Wushan County. The positive hosts were as follows, Rattus Norvegicus, Apodemus agrarius, Anourusurex squamipes, Mus musculus and Rattus flavipectus. The positive rate of HFRSV in the mice of 5 migration areas were 19.4%, 17.0%, 14.0%, 13.7%, and 8.5% respectively. The results showed that the lung tissues of some hosts in all five migration areas were HFRSV-RNA-positive. Baitao Town and Peishi Town were attributed to mixture type epidemic areas while. Kangle Town, Wansheng Village and Dachang Town were domestic rats type epidemic areas. Conclusion　This study shows that the five migration areas are natural epidemic foci of HFRS. It is predicted that maximum risk of HFRS breakout or epidemic may take place after the completion of the San Xia Reservoir(the Three-Gorges Reservoir), which results from rodent moving toward higher land. Therefore, deratization and preventive measures for rat are important in migration areas.