The Role of Wildlife and Climate Change in the Emergence of One Health-Related Viral Diseases in Australia

Wildlife-origin viral diseases are an increasing One Health challenge in Australia, with climate change emerging as a key driver of disease emergence, transmission, and spillover. Australian wildlife, particularly marsupials, birds, and bats, serve as important reservoirs of zoonotic and vector-borne viruses. However, the combined influence of wildlife reservoirs and climate change on viral disease ecology in Australia has not been comprehensively synthesised. This review examines the epidemiology, significance, and climate sensitivity of wildlife-associated viral diseases and evaluates how climate change and variability affect reservoir host ecology, vector biology, viral persistence, and host–pathogen–vector interactions. Thirteen major wildlife-associated viruses of One Health importance were identified, with transmission predominantly involving wildlife reservoirs and mosquito vectors. Temperature and rainfall were the principal climatic drivers influencing the transmission of Ross River virus (RRV), Barmah Forest virus (BFV), Murray Valley encephalitis virus (MVEV), Japanese encephalitis virus (JEV), West Nile virus/Kunjin virus (WNV/KUNV), and avian influenza A virus (AIV). For most mosquito-borne viruses (MBVs), temperature exhibited a non-linear relationship with transmission, while above-average rainfall generally increased outbreak risk by promoting mosquito abundance, habitat availability, and reservoir host activity. Significant knowledge gaps remain in wildlife virome surveillance, climate–disease pathways, and integrated One Health surveillance. Strengthening climate-informed surveillance that integrates wildlife, vectors, genomics, epidemiology, and predictive modelling will improve outbreak preparedness and reduce the risk of viral emergence and spillover in Australia.