Overview and significance of molecular methods: what role for molecular epidemiology?

In this chapter, the contribution of molecular tools in understanding the aetiology and ecology of infectious diseases is examined in the context of molecular epidemiology (ME). ME is seen as providing the 'tools', both laboratory and analytical, which have predictive significance in epidemiological investigations of the causation of disease. A diversity of questions can be addressed with these tools which can conveniently be viewed as particular regions of DNA and grouped according to the different hierarchical levels of specificity by which infectious agents can be characterized. These groupings and the applications of the different molecular tools are described, and consideration given to the most appropriate methods of analysing data from ME investigations.