From molecular to genomic epidemiology: transforming surveillance and control of infectious diseases.

The use of increasingly powerful genotyping tools for the characterisation of pathogens has become a standard component of infectious disease surveillance and outbreak investigations. This thematic issue of Eurosurveillance, published in two parts, provides a series of review and original research articles that gauge progress in molecular epidemiology strategies and tools, and illustrate their applications in public health. Molecular epidemiology of infectious diseases combines traditional epidemiological methods with analysis of genome polymorphisms of pathogens over time, place and person across human populations and relevant reservoirs, to study host–pathogen interactions and infer hypotheses about host-to-host or source-to-host transmission [1-3]. Based on discriminant genotyping of human pathogens, clonally derived strains can be identified as likely links in a chain of transmission [1-3]. In this two-part issue of Eurosurveillance, Goering et al. explain that such biological evidence of clonal linkage complements but does not replace epidemiological evidence of personto-person contact or common exposure to a potential source [3]. Muellner et al. provide clear examples how prediction about infectious disease outcome and transmission risks can be enhanced through integration of pathogen genetic information and epidemiological modelling to inform public health decisions about food-borne disease prevention [4].