Credits: Caryl and Claudin

1. ETIOLOGY OF
DISEASES

2. Etiology of Diseases
-is the study causation or origination.
-Greek word “aitiolologia” means “giving
reason for” or “cause’
-In medicine, the term refers to the causes of
diseases or pathologies where no etiology can
be ascerertained, then the disordern is said to
be idiopathic.

3. 3 Categories of Etiology
of disease
1. Genetic
-the individuals genes are responsible for
the defect
2. Congenital
-factors in the embryo’s intrauterine
environment interfere with normal
development
3. Acquired
-other factors encountered later in life
produce the disease

4. A. Factors of Disease Causation
Controllable Risk Factor
• Diet and body weight
• Daily levels of physical activity
• Level of sun exposure
• Smoking and alcohol abuse
Uncontrollable Risk Factors
• Age
• Gender
• Ethnicity
• heredity

5. B. The Natural History of Disease
-refers to a description of the uninterrupted
progression of disease in an individual from the
moment of exposure to causal agents until recovery
or death. Knowledge of the natural history of the
disease ranks alongside causal understanding in
importance for disease prevention and control.
Natural history of disease is one of the major
elements of descriptive epidemiology.

6. The iceberg phenomenon is a metaphor
emphasizing that for virtually every health problem the
number of known cases of known cases of disease is
outweighed by those that remain undiscovered, much
as the unseen part of an iceberg is much larger than
the part that is visible above the water. The iceberg
phenomenon thwarts attempts to assess the burden
of disease and the need for services, as well as the
selection of representative cases for study. This leads
to what has been called the “clinician’s policy” in
which an inaccurate view of the nature and causes of
the disease of a disease results form the studying the
minority of case of the disease.

7. Germ Theory
• Microbes as the cause of disease
• One to one relationship b/w causal agent
and diseases
Disease agent → Man → Disease

8. Epidemiological Triad
• A state of equilibrium b/w agent, host,
environment results in health. If this
equilibrium is disturbed, then disease will
occur.

9. Multifactorial Causation
Theory
• Pettenkoffer stated that agent, host and
environmental factors will act and interact
synergistically and act as joint independent.

10. Web of Causation
• Development to de-emphasize agent
• Chain of causation
• Multiple factors promote or inhibit
• Emphasizes multiple interactions
between host and environment
• Illustrates the interconnectedness of
possible causes
• Suited for chronic diseases

11. Spectrum of Disease
• Exposure
• Subclinical manifestation
• Pathological changes
• Symptoms
• Clinical illness
• Time of diagnosis
• Death
• Whether a person passes through all this stages
will depend upon infection and prevention,
detection and therapeutic measures