Natural history of a communicable disease

The natural history of a communicable disease refers to the sequence of events that happen one after another, over a period of time, in a person who is not receiving treatment. Recognising these events helps you understand how particular interventions at different stages could prevent or control the disease.

Events that occur in the natural history of a communicable disease are grouped into four stages: exposure, infection, infectious disease, and outcome (see figure below). We will briefly discuss each of them in turn.