Alphaviruses comprise a fascinating group of small, enveloped single-stranded positive-sense RNA viruses. They are usually transmitted by arthropod vectors (usually mosquitoes). Of the thirty known species, eight are important human pathogens (e.g. Venezuelan equine encephalitis virus) whilst one, salmonid alphavirus, is of economic importance to the farmed fish industry. Due to their small size alphaviruses have historically been utilised as model systems for the analysis of viral pathogenesis. Understanding alphavirus molecular biology, pathogenesis and host interactions are key areas of...