Climatic Associations of Akabane Virus Occurrence in East Asia: Temperature-Driven Patterns Based on the Köppen-Geiger Classification.

Akabane virus (AKAV) is a Culicoides-borne arbovirus that causes congenital malformations and reproductive losses in ruminants, resulting in substantial economic losses in livestock production. Because vector activity and virus transmission are strongly influenced by environmental conditions, defining climatic factors associated with AKAV distribution is critical for understanding its epidemiology. However, such relationships have not been systematically evaluated in East Asia. In this study, we applied the Köppen-Geiger climate classification to characterize regional climatic zones in South Korea and Japan and examined their associations with AKAV case counts. AKAV cases were predominantly observed in temperate climate zones (Cfa and Cwa). Temperature-related variables showed consistent positive associations with AKAV case counts, with a 1 °C increase in annual mean temperature associated with approximately 1.38-1.56-fold increases in reported cases. In contrast, precipitation variables exhibited weak or negative associations. These findings indicate that temperature is an important climatic factor associated with AKAV case counts, suggesting that climate-dependent modulation of vector dynamics may contribute to observed patterns of AKAV occurrence. This study provides a climate-based framework for understanding the spatial distribution of AKAV and supports the development of targeted surveillance and control strategies under changing environmental conditions.