Climate-driven changes in zoonotic risk of arenaviral hemorrhagic fevers in South America.

Climate change is expected to significantly alter the ecological dynamics of zoonotic diseases, yet its long-term impact on rodent-borne hemorrhagic fevers in South America remains poorly understood. Here, we developed a robust predictive modeling framework that integrates species distribution models with a mechanistic force-of-infection approach to evaluate the effects of climate change on zoonotic risk of New World Arenaviruses. Using climate projections under Shared Socioeconomic Pathways SSP2-4.5 (moderate) and SSP5-8.5 (severe), our models predict a substantial increase in spillover risk across endemic and non-endemic regions over the next two decades. Projected increases in spillover risk for Guanarito, Machupo, and Junin viruses are primarily driven by climate-induced shifts in temperature seasonality, reduced precipitation, and expanding anthropogenic land use, particularly cropland and urban areas within reservoir habitats. Our projections identify transboundary arenaviral hotspots, underscoring the urgent need for coordinated climate-adaptive public health policies, including cross-border surveillance efforts, land-use planning, and resilient rural health systems.