Tracing more than two decades of Japanese encephalitis virus circulation in mainland China

Japanese encephalitis virus (JEV) is the cause of Japanese encephalitis, a significant health concern in China. Despite being one of the most studied mosquito-borne viruses, no previous studies have combined genomic and geographic data to investigate the spatial epidemiology and dispersal capacity of the virus. In this study, we analyzed genomic, geographic, and environmental data to trace the dispersal history of JEV in China and explore the environmental factors influencing its distribution. Our findings show that JEV circulates predominantly in areas with higher temperatures, dense human and pig populations, and favorable conditions for <i>Culex</i> mosquitoes. Notably, our analyses showed a higher diffusion capacity of JEV compared to co-circulating viruses, possibly driven by factors like pig trade and bird migration. Our analysis calls for improved genomic surveillance and establishes a baseline for future studies on the effects of climate change, agricultural practices, and bird migration on JEV circulation.