Surveillance and Analysis of Hemorrhagic Fever with Renal Syndrome (HFRS) from 2002 to 2004 in Quzhou City

Objective This study was conducted to understand the epidemic mode and epidem-iC foci situation of hemorrhagic fever with renal syndrome (HFRS)．SO as to provide evidence for HFRS control．Methods By applying descriptive epidemiology methods and epidemic foci sue-vey，epidemic situation among humans and the main host animals were analyzed．Samples were collected and then were sent to the laboratories．The antibody was determined by indirect im-munofluorescence assay while the antigen was determined by direct immunofluorescence assay．Results There were all together 294 HFRS cases during the 3 years and the average annual mot-bidity rate was 4.01/lakh．Besides．There was one death case and the mortality rate was 0.33％．The disease was distributed throughout 78 towns and counties．Accounting for 54.55％ 0f all towns and counties in that area．The onset seasons showed a double peak mode for incidence with Deak incidence ratio of winter to spring 1.29:1．Farmers accounted for 83.67％ of all patients who had the disease and the ratio of the male to the female was 2.54:1．The incidence number of group between the age 0f 20 to 59 accounted for 81.29％．Moreover．The rat density in the open air was 3.64％ whereas the corresponding one indoors was 3.68％．The brown rattus andersoni and aoode-mus agrarius were predominant in rats indoors and outdoors．With toxic index of 0.026 and 0.034 respectively．The toxic indexes of rat were respectively 0.048，0.036，and 0.032 during the 3 years，correlating with the change of morbidity rate．Conclusion During the 3 years in Quzhou，HFRS morbidity，recessive infection rate among population，and the toxic index of rat for the main host. Were all JOW, which were basically the same with the surveillance situation in the province and all over the country．Indicating that the onset of HFRS was in accordance with the natural law of fluctuating with the year．Quzhou was further transformed to mixed epidemic area．Furthermore，it was verified tllat the toxic index of rat was correlated with morbidity rate．