Microbiology: introduction to micro-organisms; major structural components of bacteria; mutualism, indigenous microbiota; determinants of virulence; Pathogen-associated molecular pattens; Virology: virus structure and classification; viral pathogenesis, viral interactions and immune evasion. Immunity: introduction to immunity; innate defences against infection; pattern recognition receptors; cell biology of the specific immune system; humoral specific immunity; cell mediated specific immunity; generation of immunological diversity.