Climate drivers of tick-borne encephalitis in the Veneto Region, Italy, 2007-2024

Tick-borne encephalitis (TBE) is an arboviral disease in Europe, with increasing incidence in northeastern Italy. Transmission of the virus via Ixodes ticks is influenced by seasonal dynamics and environmental factors. This study aimed to describe TBE epidemiology in the Veneto Region, assess spatiotemporal patterns, and examine associations with environmental determinants, including possible impacts of climate change. We conducted a population-based study using hospital discharge records to identify TBE cases from 2007 to 2024. Temporal trends and spatial patterns of age-standardized incidences were assessed. A generalized additive mixed model was fitted to evaluate non-linear associations between TBE incidence and environmental predictors. Scenario-based analyses simulated changes in temperature and precipitation to estimate shifts in TBE risk. A total of 397 TBE hospitalizations were recorded, predominantly in mountainous areas (55.4%), with seasonal peaks in June and July. Age-standardized incidence significantly increased from 2014 to 2024, with an annual percentage increase of 10.2%, reaching 0.855 cases per 100,000 person-years in 2022. Changes in age-specific incidence were observed over time, with increasing trends particularly among children and adolescents. Monthly minimum temperature and forest land cover percentage emerged as key drivers of TBE risk, with U-shaped associations for precipitation and altitude. Scenario simulations suggested a maximum increase in incidence of 16% per 0.5 °C rise in minimum temperature, particularly in high-altitude municipalities. TBE hospitalizations in the Veneto Region show marked spatial, temporal, and age-related heterogeneity. Climate change is likely to increase incidence and expand at-risk areas, underscoring the need for integrated One Health surveillance and targeted prevention strategies.