Abstract: Objective  To investigate the epidemiological characteristics of hemorrhagic fever with renal syndrome(HFRS) and analyze the seasonal distribution characteristics, so as to provide a reference for the prevention and treatment of this condition. Methods  Retrospective analysis was performed in laboratory confirmed cases of hemorrhagic fever with renal syndrome treated in the First Affiliated Hospital of Wannan Medical College between July 2010 and September 2020. Concentration degree and circular distribution method were used to analyze the seasonal clustering strength of onset time. Results  The concentration of HFRS cases from 2010 to 2020 was M=0.54, indicating that the peak of HFRS was in seasonal fashion. The results of circular distribution analysis showed that the onset time of HFRS patients presented a bimodal distribution. The peak days of the total cases in spring and summer (main peak) as well as autumn and winter (second peak) were May 15 and January 7, respectively, and the peak days were April 4 to June 25 and December 3 to February 12 of the following year, respectively. The Watson-Williams test was used to analyze the differences of peak days and peak periods between male and female HFRS cases. The results showed that there was no significant difference in peak days and peak periods between spring and autumn (March-August) (F=3.28, P>0.05) and autumn and winter (September to February of the following year) (F=0.069, P>0.05). That is, there is no difference in the peak day and peak of HFRS between male and female case groups. Conclusion  The concentration degree and circular distribution method are advantageous to quantitatively and accurately calculating the actual peak day and peak interval of HFRS. The incidence time of 124 HFRS cases reported in our hospital was in seasonal fashion between 2010 and 2020, and the epidemic trend showed a double-peak type of main and sub-peak, with the main peak from April to June. The second peak was from December to February of following year. 

Key words: Hemorrhagic fever with renal syndrome, Seasonality, Concentration ratio, Circular distribution