Epidemiological study on hemorrhagic fever with renal syndrome in flood areas

To investigate the infection of hemorrhagic fever with renal syndrome (HFRS) in host animals and inapparent infection of HFRS in general population in Dongting Lake areas after floods.

The night trapping method was used to capture rodents. The immunofluorescence assays were used to detect the hantavirus (HV) antigens and antibodies in rodents lung and in the serum of general population. Nonconditional logistic regression was applied to analyze risk factors for inapparent infection with HV.

In flood region,draw-near flood region and new migration region,rodent density was 6.95%,6.28%, and 8.67%, respectively, and the virus-carrying rate in rodents was 15.07%,9.25%, and 4.47%, respectively. The virus-carrying rat index was the highest in flood region (0.10). Apodemus agrarius was the dominant species. The standardized positive rate of HV antibody in general population from above mentioned regions was 4.49%, 3.11%, and 3.13%, respectively. There was no significant difference among different age or gender groups. The results of logistic regression analysis indicated that people who were involved in construction of water conservancy facilities in winter or practice of rat extermination at home were the principal factors related to inapparent infection with HV.

The virus-carrying rate in main host animals of HV in the 3 regions is high, whereas the positive rate of HV antibody is low in general population. Comprehensive measures should be taken to prevent and control HFRS, such as reinforcing surveillance of HFRS, strengthening deratization, and preventive inoculation.