My research integrates ideas from a number of scientific fields including evolutionary genetics, virology, ecology, and infectious disease epidemiology. I conduct human and animal disease surveillance, virus isolation and characterization (genetic and phenotypic), then conduct large-scale analyses to generate hypotheses that are tested in the laboratory using tissue culture and animal models. I am primarily interested in the roles played by mutation, natural selection, recombination/reassortment and host immune response on virus diversity within an individual, during transmission within a population and during inter-species transmission between hosts. I work mostly on influenza but also study a wide range of respiratory and enteric viruses. My research program is directed at efforts to better understand viral disease ecosystems in Asia, specifically the animal-human interface, to inform and enhance disease control.