Investigation of outbreaks: epidemiology.

Outbreaks of Legionnaires' disease create high levels of public anxiety and media interest and inevitably consume a great deal of public health resources. Investigations should begin as early as possible in order to rapidly identify suspected sources of infection, control the outbreak and prevent further cases occurring. The investigations should be coordinated by an outbreak control team who work collaboratively within local/national/international public health guidelines and with clear terms of reference. The actions carried out by epidemiologists when investigating community-, hospital-, or travel-associated outbreaks are comprehensively outlined in this chapter. The microbiological and environmental actions that complement this work are discussed in the accompanying chapters.