1.3 Natural history of a communicable disease
The natural history of a disease is also referred to as the course of the disease, or its development and progression; these terms can be used interchangeably.
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. (You will learn about this in detail in Study Session 2.)
Events that occur in the natural history of a communicable disease are grouped into four stages: exposure, infection, infectious disease, and outcome (see Figure 1.6). We will briefly discuss each of them in turn.
1.2.6 Susceptible hosts and risk factors