Monitoring of hemorrhagic fever with renal syndrome in Yunnan province,China,2005

Objective To understand epidemiological characteristic of hemorrhagic fever with renal syndrome(HFRS) and provide information for control and prevention of HFRS in Yunnan province. Methods The data of cases of HFRS was collected in Yunnan province and human sera, the lung tissue and sera of rodents were collected in the surveillance counties. Then the antibody and antigen of Hantavirus was detected. Results The 46 cases had been reported in Yunnan province in 2005. The incident rate was 0.103/100 000. The main attacking areas were Dali prefecture, Kunming city and Honghe prefecture. The 8 species of 713 rodents had been captured and the 262 rodent sera and 407 human sera had been collected in Luxi, Xundian and Yongsheng counties where are surveillance areas. Rattus norvegicus and R.flavipectus were the dominant species in human living areas and Apodemus chevrieri was the dominant species in the fields. The Hantavirus carrying rate was 3.22%(23/713) in rodents and the rodents carrying virus were R.norvegicus, R.flavipectus, A.chevrieri, Eothenomys miletus and Suncus murinus. The positive rate of the antibody in human and rodent was 3.19%(13/407) and 4.96%(13/262) respectively. The latent infected rate was 3.00%(3/100) in Luxi county in the spring and summer. However the rate was 5.13%(4/78) in the autumn. So the rate was higher in the spring and summer than that in the fall. Conclusion There are the Rattus epidemic foci with the main hosts of R.norvegicus and R.flavipectus and there are also the Apodemus epidemic foci with the main hosts of A.agrarius and E.miletus in the surveillance areas. The increasing incident rate is related to the high rodents density and the rate of infected virus in the rodents.