Surveillance of hemorrhagic fever with renal syndrome(HFRS)in TaiZhou City from 2000 to 2005

Objective This study was designed to explore the epidemic characteristics of hemorrhagic fever renal syndrome (HFRS) for providing dada for the formulation of stratigies for its prevention and treatment. Methods Epidemiology, field survey, laboratory etiology and serology were used in the analysis. Results The incidence rate of HFRS were 3.63/lakh (4.50/lakh-2.64/lakh), average annual mortality 0.02/lakh thousand and case fatality rate 0.42% in Taizhou from 2000 to 2005. Cases of HFRS were mainly distributed in Tiantai, LinHai and Jiaojiang County, accounting for 73.43% of the cases in the whole city, while 12.62% burgh had 46.33% of the cases. Epidemic peaks were observed in periods of winter to spring and summer to autumn in mixed-type infectious area, where Apodenmus agrarius played the dominant role. Peasants at prime of life and at older age made up the major group of the infected, incidence rate 86.54%.The sub-clinical infection rate of healthy people in the epidemic area was 1.98%. In the five years' animal surveillance, the total outdoor mouse density was 4.61%, capture rate of Apodenmus agrarius 3.59%, while the indoor density was 2.67% and density of Rattus norvegicus 1.99%, the predominant species of mouse being Rattus norvegicus and Apodenmus agrarius in residential areas. The HV carring rate of the mice was 17.00% (0.90%-36.40%), and index of HV carriers was 0.02-0.14, averagely 0.08. Conclusion The incidence rate of HFRS presents an obvious declining trend in Taizhou from 2000 to 2005. HFRS prevention and control in main areas should be strengthened. Double-value united vaccine can be used for vaccination in mixed-type epidemic areas dominated by Apodenmus agrarius.