'Course of a disease process without any intervention' is the definition of
Natural history of disease refers to the progression of a disease process in an individual over time, in the absence of treatment Spectrum of disease signifies that the health of an individual is not static Ref : Park's Textbook of Preventive and Social Medicine; 23rd edition - Pgno. 34
Spectrum of disease
Epidemiology of disease
Natural history of disease
Iceberg Phenomenon
Concept of health and disease