The document discusses the natural history of disease in the following areas: 1. It describes the phases a disease progresses through without treatment, including pre-pathogenesis, pathogenesis, and incubation periods. 2. It outlines several factors that can influence disease, including agent factors (e.g. viruses, bacteria), host factors (e.g. age, genetics), and environmental factors (e.g. physical, social). 3. It discusses concepts in disease prevention and intervention, including primordial, primary, secondary, and tertiary prevention as well as modes of intervention like health