Our laboratory is undertaking basic research on the development of vaccines against the flavivirus diseases. This includes West Nile, Japanese encephalitis, yellow fever and dengue. We undertake studies on the excellent yellow fever 17D vaccine as a model to understand the molecular basis of attenuation of this vaccine. This is of major importance as the 17D vaccine virus is being used as an attenuated backbone to generate chimeric vaccine viruses against other flavivirus diseases, including dengue and Japanese encephalitis. In addition, recombinant DNA technology and infectious clone technology/reverse genetics are being used to identify molecular determinants of virulence of yellow fever, West Nile and Japanese encephalitis viruses with the aim of mutating these virulence determinants to develop candidate attenuated vaccine strains. We also investigate the molecular epidemiology of various flaviviruses (yellow fever, West Nile, Japanese encephalitis, and St Louis encephalitis viruses).