Risk of hemorrhagic fever with renal syndrome associated with meteorological factors in diverse epidemic regions: a nationwide longitudinal study in China.

Background: Hemorrhagic fever with renal syndrome (HFRS) is a climate-sensitive zoonotic disease that poses a significant public health burden worldwide. While previous studies have established associations between meteorological factors and HFRS incidence, there remains a critical knowledge gap regarding the heterogeneity of these effects across diverse epidemic regions. Addressing this gap is essential for developing region-specific prevention and control strategies. This study conducted a national investigation to examine the associations between meteorological factors and HFRS in three distinct epidemic regions.

Methods: We collected daily meteorological data (temperature and relative humidity) and HFRS incidence cases of 285 cities in China from the Resource and Environment Science and Data Center and the Chinese National Notifiable Infectious Disease Reporting Information System from 2005-2022. Study locations were stratified into three distinct epidemic categories (Rattus-dominant, Apodemus-dominant, and mixed) based on the seasonality of peak incidence. The associations between meteorological variables and HFRS incidence were investigated using a time-stratified case-crossover design combined with distributed lag nonlinear modeling for each epidemic category.

Results: The exposure-response relationships between meteorological factors and HFRS incidence revealed significant heterogeneity across epidemic regions, as evidenced by Cochran's Q test for temperature (Q = 324.40, P < 0.01) and relative humidity (Q = 30.57, P < 0.01). The optimal daily average temperature for HFRS transmission in Rattus-dominant epidemic regions (- 6.6 °C), characterized by spring epidemics, was lower than that observed in Apodemus-dominant epidemic regions (13.7 °C), where primary cases occurred during autumn and winter months. Furthermore, the association between relative humidity and HFRS incidence exhibited as a monotonic negative correlation in Rattus-dominant regions, while Apodemus-dominant regions showed a nonlinear, inverted U-shaped association.

Conclusions: This study highlights the heterogeneous effects of meteorological factors on HFRS incidence across different epidemic regions. Targeted preventive measures should be taken during cold and dry spring days in Rattus-dominant regions, and during warm and moderately humid winter days in Apodemus-dominant regions. In mixed epidemic regions, both scenarios require attention. These findings provide novel scientific evidence for the formulation and implementation of region-specific HFRS prevention policies.