Surveillance of Hemorrhagic Fever with Renal Syndrome in Yunnan Province, China, from 2001～2002

Objective To understand epidemiological characteristics of Hemorrhagic Fever with Renal Syndrome (HFRS) for offering a guidance of control and prevention of HFRS in Yunnan Province. Method Collecting the data of cases of HFRS in Yunnan Province and collecting human sera and the lung tissue and sera of rodents in the surveillance counties and detecting the antibody and antigen of Hattanvirus. Result 102 cases and 3 deaths had been reported in Yunnan Province in 2001 and 2002. The incident rate was 0.12/ 100 000 and the case fatality rate was 2.97%. The main attacking areas were in Honghe Prefecture, Kunming City and Chuxiong Prefecture. The inapparent infection rate was 4.19% in population in the epidemic areas. 9 species of 891 rodents had been captured in Luxi, Xundian and Yongshen counties where are surveillance areas. Rodents of Rattus norvegicus and Rattus flavipectus were the dominant species in human living areas and rodent of Apodemus agrarius was the dominant species in the fields. The Hattanvirus carring rate was 3.65% in rodents and the virus-carrying rodents were Rattus norvegicus, Rattus flavipectus,Mus musculus and Apodemus agrarius. 12 species of 140 rodents had been captured in the fields of Dali City in 2001 and rodent of Eothenomys miletus was the dominant species. The rodents of virus-carring were Eothenomys miletus,Rattus nitidus, Rattus flavipectus, Niviventer confucianus and Anowrosorex squamipesi squamipes. Conclusion There are the Rattus foci with the hosts of the main rodents of Rattus norvegicus and Rattus flavipectus and there are the Apodemus foci with the host of the main rodents of Apodemus agrarius and Eothenomys miletus too in the surveillance areas. The incidence had been increasing as the density of rodents and the rate of virus infection in the rodents went up. It should be taken measures of rodent elimination and seoul type or mixed type vaccination for HFRS prevention.