Epidemic Characteristics and Spatio-Temporal Patterns of HFRS in Qingdao City, China, 2010-2022*

Objective This study investigated the epidemic characteristics and spatio-temporal dynamics of hemorrhagic fever with renal syndrome (HFRS) in Qingdao City, China. Methods Information was collected on HFRS cases in Qingdao City from 2010 to 2022. Descriptive epidemiologic, seasonal decomposition, spatial autocorrelation, and spatio-temporal cluster analyses were performed. Results A total of 2,220 patients with HFRS were reported over the study period, with an average annual incidence of 1.89/100,000 and a case fatality rate of 2.52%. The male:female ratio was 2.8:1. 75.3% of patients were aged between 16 and 60 years old, 75.3% of patients were farmers, and 11.6% had both "three red" and "three pain" symptoms. The HFRS epidemic showed two-peak seasonality: the primary fall-winter peak and the minor spring peak. The HFRS epidemic presented highly spatially heterogeneous, street/township-level hot spots that were mostly distributed in Huangdao, Pingdu, and Jiaozhou. The spatio-temporal cluster analysis revealed three cluster areas in Qingdao City that were located in the south of Huangdao District during the fall-winter peak. Conclusion The distribution of HFRS in Qingdao exhibited periodic, seasonal, and regional characteristics, with high spatial clustering heterogeneity. The typical symptoms of "three red" and "three pain" in patients with HFRS were not obvious.