Analytical surveillance of hemorrhagic fever with renal syndrome in Yunnan Province,China in 2009

Objective To understand epidemiological characteristic of hemorrhagic fever with renal syndrome(HFRS) for offering a guidance to control and prevention of HFRS in Yunnan Province. Methods Data of cases with HFRS in Yunnan Province,human sera and the lung tissues of rodents in the surveillance counties were collected to detect antibody and antigen to Hantavirus. Results There were totally 16 cases and one death case reported in Yunnan Province in 2009 with incidence rate of 0.04/100 000 and case fatality rate of 6.25%. The main attacking areas were in Dali Prefecture,Kunming City,Honghe Prefecture,Wenshan Prefecture,Chuxiong Prefecture and Nujiang Prefecture. There were 559 rodents of 15 species of 8 genera captured,and 292 human sera were collected in surveillance areas including Wuhua District of Kunming City,Luxi and Xiangyun County. The rodents of Rattus norvegicus and Rattus flavipectus were the dominant species in human living areas and the rodents of Apodemus agrarius and Eothenomys miletus were the dominant species in the fields. The carrying rate of Hatanvirus was 3.78%(20/529) in rodents,including Rattus norvegicus,Rattus flavipectus,Mus musculus,Rattus niti,Eothenomys miletu,Suncus murinus and Crocidura attenuate. The positive rate of the antibody in healthy human was 4.45%(13/292) . Conclusions It is confirmed that there are the Rattus foci of HFRS with the hosts of the main rodents of Rattus norvegicus and Rattus flavipectus and there are also Apodemus foci with the host of the main rodents of Apodemus agrarius and Eothenomys miletus in the surveillance areas. The incidence decreases as the density of rodents and the rate of infected virus in the rodents reduce.