م.م حميد عثمان مشعان

Definition of basic terms: Communicable disease: An illness due to specific infectious agent or its toxic products which develops through transmission of that agent or its toxic products from a reservoir to a susceptible host either directly or indirectly. Contagious disease - capable of spreading from one person to another Incubation period: The interval between exposure and first clinical manifestation. The time between exposure and first case is the minimum incubation period, The time between exposure and the last case, maximum incubation period.

Learning Objectives for the Lecture:
At the end of the lecture the student is going to be able to:
1. Describe the natural history of heath conditions.
2. Describe the stages of the natural history of heath conditions.
3. Describe the process of prevention.
4. Describe the levels of prevention.
Natural History of Health-related Conditions:
The natural history of health condition is a description of the events that precedes the development of the health condition, and during its occurrence through the course of development, as well as its outcome.

Learning Objectives for the Lecture:
At the end of the lecture the student is going to be able to:
1. Define epidemiology and related concepts.
2. Describe the purpose of epidemiology.
3. List the uses of epidemiology.
4. Identify the term of causality and its related terms.
5. Describe the epidemiological triad and the variations among its elements.
Simple Old Definitions
1. Study the occurrence of illnesses.
2. Branch of medical science which treats epidemics (Oxford English Dictionary).