Question: Define epidemiology.
Answer:
Epidemiology is the study of the distribution and determinants of health-related events in populations and the application of this study
to control health problems.
Question: There are two principal types of epidemiology: (1) analytic epidemiology and (2) descriptive
epidemiology. Describe each.
Answer:
Descriptive Epidemiology
Descriptive epidemiology studies:
who is affected
where the disease occurs
when the disease occurs
It identifies patterns and trends in populations.
Example:
Tracking influenza outbreaks by age, location, and season.
Analytic Epidemiology
Analytic epidemiology investigates:
why disease occurs
causes and risk factors
relationships between exposures and outcomes
, Example:
Studying whether smoking increases the risk of lung cancer.
Question: Explain the epidemiological triangle model of agent-host-environment, Wheel Model and the
web of causation model.
Answer:
Epidemiological Triangle Model
This model explains disease interaction among three components:
Agent: cause of disease
Host: susceptible person
Environment: external conditions that promote disease transmission
Example:
For influenza:
Agent = influenza virus
Host = unvaccinated person
Environment = crowded indoor setting
Wheel Model
The Wheel Model places the genetic core of the host at the center, surrounded by biologic, physical, and social environments. It
emphasizes environmental influences on disease development, especially chronic diseases.
Web of Causation Model
This model shows that disease develops from many interconnected factors rather than a single cause.