Epidemiology Flashcards
Studies the pattern of disease
occurrence in human populations and
the factors that influence this
pattern.
Epidemiology
The term is related to epidemic
(derived from the Greek word “________”) meaning leading the
people
upon the people
- father of modern epidemiology
- Study about ____
- Snow would not have been
formulated his hypothesis without
the ____ he gathered
John snow
cholera
data
The absence or presence of a disease
health
Must be “clearly defined”
Good health
State of physiological/biomedical
dysfunction
disease
Subjective state/awareness of not being well
Illness
state of social dysfunction (the “sick
role”)
sickness
Any loss of abnormality of structure or
function
Impairment
Restriction or inability to perform in the
manner considered normal of an individual
Disability
Disadvantage that limits or prevents the
fulfillment of a social role
Handicap
an increase in the frequency (incidence) of a
disease above the usual and expected rate, which is
called the _____ thus epidemiology count cases of a disease, and
when they detect the sign of epidemic, they ask
___, ___ and __ questions.
epidemic rate
who, when, where
surveillance made by
the government before many people start
dying.
notifiable disease
In epidemiology of any disease or event, one
studies the factor which contribute to its
causation and behavior
agent, host, environment
is any element, substance or force
whether living or non-living
thing; the presence or absence can
initiate or perpetuate a disease
process.
agent
types of agent
- living or nonliving things, physical or mechanical, light electricity
- chemicals - endogenous (within the body) or exogenous (poison)
inherent characteristics (4)
physical features
biological requirement
chemical composition
resistance
Characteristic in relation to the environment
reservoir
source of infection
modes
of transmission
Characteristic directly related to man (VAIP)
Infectivity
Pathogenicity
Virulence
Antigenicity
immediate transfer of infectious
agent a receptive portal of entry
Direct transmission
Indirect transmission
a. _____ - contaminated inanimate objects or
materials
b. _____- from other living organism
(ex. Insects)
Vehicle borne
Mechanical/Vector borne
dissemination of microbial aerosols to a
suitable portal of entry usually the respiratory tract
airborne
2 airbone
droplet nuclei, dust
THE HOST FACTOR OF DISEASE (6)
- Age
- Sex
- Race
- Habits, Customs, and religions
- Exposure to agent
- Defense mechanism of the host
This is the total property of an
individual to protect himself from
an infectious agent
immunity
Two types of immunity
non specific resistance
specific resistance
present at the
time of birth or has developed during
maturation
non specific resistance
acquired as a
result of prior exposure with a foreign
substance
specific resistance
TWO FOLDS OF SPECIFIC RESISTANCE
Active and passive
what has been introduced to the individual is the
antigen and the body makes the antibody.
active
when what has been introduced to the body is already
antibodies that provide immediate protection against
microorganisms.
passive
exhibited by the
transfer of antibodies from mother’s placenta to the fetus
and transfer of antibodies from breast milk to the baby
Naturally acquired passive immunity
injection of
artificially prepared substance like immune serum of gamma
globulin. These two are antibodies preparation (ex. Antitetanus antibodies, diphtheria antitoxin)
Artificially acquired passive immunity
when we get sick the
infective agent will gain entry to the body, act as stimulant
for antibody formation because the organism acts as antigen.
- The immunity is lifelong (ex. Measles, chicken pox,
hepatitis A)
Naturally acquired active immunity
when the antigen has
been deliberately introduce like injecting vaccines, they act as
antigen to stimulate antibody formation.
- It makes use of vaccine which is suspension of killed or
living organism (ex. MMR,OPV,BCG)
Artificially acquired active immunity
sum total of an organism’s external
surrounding conditions and influences that affect
its life and development
environment
THE ENVIRONMENTAL FACTORS OF DISEASE
- Physical Environment
● climate
● Geography and location
● Biologic Environment
● Socio-economic environment
Time between exposure to infectious agent up to the time
of appearance of the earliest signs and symptoms
Incubation Period
the time between exposure
to a pathogenic organism and the onset of symptoms of a
disease.
Clinical incubation period
The time taken by the
parasite to complete its development in the definite
host
Biological Incubation Period
As applied to patient, separation for the period of
communicability, of infected persons or animals from
others in such places and under such conditions as to
prevent or limit the effect of the direct or indirect
transmission of the infectious agent from those infected
to those who are susceptible or who may spread the
disease agent.
isolation
Types of Isolation
- Source isolation
- Protective isolation
The patient is the source of infection
source isolation
The patient requires protection
protective isolation
Restriction of the activities of
well persons or animals who have
been exposed to a case of
communicable diseases during its
period of communicability to prevent
disease transmission during
incubation of infection should occur
Quarantine
Limitation of movement of those
exposed to a communicable disease
for a period of time not longer
than the longest usual incubation
period of that disease.
Absolute or Complete Quarantine
Selective, partial limitation of
freedom of movements of contacts
Modified Quarantine
THE DIFFERENT EPIDEMIOLOGIC
STUDIES
- Descriptive Study
- Experimental Study
DESCRIPTIVE STUDY
Analytical Study:
- Ecological
- Cross-sectional
- Case-Control
- Cohort
EXPERIMENTAL STUDY
Randomized control trial
field trial
community trial
It is an epidemiological experimental study of a new
preventative or therapeutic regimen.
Randomized Control Trial
It involves people who are disease free
but presumed to be a risk.
Field trials
In this form of experiment the treatment groups
are the communities rather than individuals.
Community trials
2 phases
Pre-pathogenesis
Pathogenesis
This is the phase before man is involved.
Pre-pathogenesis
This phases includes the successful invasion and
establishment of the agent in the host
Pathogenesis
