Climate change and the growing threat of bunyaviruses.

Anthropogenic climate change and its implications for infectious diseases have been central to the scientific and public health discourse for more than three decades. In 2026, we have now entered a climate adaptation phase, with accumulating evidence demonstrating that ongoing climatic variability is directly reshaping the dynamics of multiple vector-borne viruses, including bunyaviruses. Bunyaviruses comprise a diverse group of segmented, negative-sense RNA viruses that include significant human and veterinary pathogens, such as Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, Oropouche virus, and Cache Valley fever virus. Despite their medical and veterinary importance, climate-virus relationships remain comparatively less well characterized for bunyaviruses than for viruses such as dengue, Zika, chikungunya, and yellow fever. This gap is increasingly notable in light of recent epidemiological shifts, exemplified by the 2022-2025 expansion of Oropouche virus across the Americas and the Caribbean, which highlights how bunyaviruses can exploit ecological disruption and underscores the need to better understand the environmental determinants of their transmission. Advances in genomic surveillance, experimental virology, and climate-informed epidemiology now enable these interconnected virus-host-vector-environment dynamics to be examined with increasing precision. In this minireview, we synthesize current evidence linking environmental change to bunyavirus transmission and geographic expansion, identify critical mechanistic and surveillance gaps, and outline priorities for developing predictive frameworks to strengthen bunyavirus preparedness within a One Health context.