Climate Change and Epidemic Preparedness: High-Risk Regions of Japanese Encephalitis Virus in Victoria, Australia, From 2021 to 2100

In 2022, an unexpected Japanese encephalitis virus (JEV) outbreak affected Australia, causing human and pig infections. Climate conditions were previously found to be risk factors of JEV outbreaks. Hence, understanding their future risk due to climate change can help inform public health authorities of the potential JEV risk, particularly in nonendemic areas such as Victoria, Australia. Following up on a previous investigation, this study aimed to identify regions in Victoria, Australia, that might present high-risk areas of JEV in future climatic scenarios. An analytical hierarchy process with an expert panel was the methodology implemented to analyze the risk of JEV under 2 emission scenarios: SSP1-2.6 (low emission) and SSP5-8.5 (very high emission) from 2021 to 2100. Victoria showed more high-risk areas of JEV than the historical risk during the summer months under both emission scenarios and for all periods. Gippsland, Hume, and the Melbourne Metropolitan areas were the most vulnerable regions to JEV risk, with more high-risk areas also in the autumn and spring months under the SSP5-8.5 emission scenario. Climate change could exacerbate the presence of high-risk areas of JEV in Victoria, Australia, in the immediate and distant future. These results underline the urgency of preparing for outbreaks and epidemic events, particularly in regions of Victoria not currently categorized as high-risk for flavivirus outbreaks.