Project Summary New solutions are desperately needed to reduce the annual global burden of dengue. As we have witnessed for SARS-CoV-2, virus genomics can be harnessed to directly inform public health control measures. However, for most other pathogens, including dengue virus, the depth of genomic information needed for such applications is lacking. For dengue virus, part of the issue is its complexity: it is comprised of four genetically distinct serotypes with many defined genotypes and even more undefined variants. Furthermore, current surveillance and research programs are not optimized to fully leverage virus genomics. This proposal aims to bridge this gap by proposing a detailed phylogenetic analysis to uncover critical dengue epidemiological processes, including the outbreak emergence interval and pattern of spread. Through this initiative, our understanding of dengue virus diversity, evolution, and epidemiology will significantly advance. The proposed research, which integrates insights from the COVID-19 pandemic and the 2014-2016 West African Ebola outbreak, aims to determine which DENV lineages were integral to past outbreaks and explore the temporal and geographic factors influencing their persistence. The anticipated outcomes encompass the identification of DENV lineages responsible for causing outbreaks, estimation of average emergence intervals, and insights into the factors impacting lineage persistence. These findings can revolutionize DENV disease forecasting and contribute to the development of genomics-informed control strategies, offering a timely and vital approach to addressing the escalating challenge of dengue transmission globally.