We study the dynamics and evolution of infectious diseases within individuals and across populations. By developing mathematical models and computational tools to understand disease dynamics across scales, we aim to guide the design of medical interventions and public health control programs. Past and present work has focused on HIV/AIDS, SARS-CoV-2/COVID-19, RSV, KSHV, and antimicrobial resistance. Recurring themes of our work include disease dynamics in structured populations, evolution in fluctuating environments, the interaction of behavior with disease dynamics, inferring dynamic models from diverse data sources, and education at the interface of mathematics and biology.