Download communicable diseases

CONCEPT OF
DISEASE
COMMUNITY RESEARCH
PROGRAM 1
FAJAR AWALIA YULIANTO
The modern Epidemiology :
“Using quantitative methods to study ,
prevent, and control the disease in human
population”
CAUSATION OF DISEASE
GENETIC FACTOR
GOOD HEALTH
POOR HEALTH
ENVIRONMENTAL FACTORS
(INCLUDING BEHAVIOURS)
EVALUATING
INTERVENTIONS
TREATMENT
MEDICAL CARE
GOOD HEALTH
HEALTH PROMOTION
PREFENTIVE MEASURES
PUBLIC HEALTH SERVICES
ILL HEALTH
DEFINITION

HEALTH


Health is a state of complete physical, mental and
social well-being and not merely the absence of
disease or infirmity
DISEASE

Conformed in epidemiology, as simple as
“disease present” and “disease absent”
NATURAL HISTORY OF
DISEASE
Death
Good health
Sub-clinical changes
Clinical changes
Recovery
THE CONCEPT OF CAUSE

A cause of a disease or injury is an event,
condition, characteristic or a combination of
these factors which plays an important role in
producing the health outcome
IS THE CAUSE SUFFICIENT OR
NECESSARY FORMING THE DISEASE?

Sufficient if:


It inevitably produces or initiates an outcome
Necessary if:

An outcome can not develop in its absence
EACH SUFFICIENT CAUSE HAS A NECESSARY
CAUSE AS A COMPONENT
FACTORS IN CAUSATION




Predisposing factors : age, sex, genetic traits
and previous illness may create susceptibility
Enabling (Disabling) factors : low income, poor
nutrition, bad housing and inadequate medical
care may favor the development of illness
Precipitating factors : exposure to a specific
disease agent or noxious agent may be
associated with the onset of disease
Reinforcing factors : repeated exposure,
unduly hard work may aggravate an
established disease or injury
TRADITIONAL MODEL OF INFECTIOUS
DISEASE CAUSATION
AGENT

as an element or substance, animate or in
animate,the presence (or absence) of it
may initiate or perpetuate a disease
process.
COMPONENTS OF AGENT




Nutritional
Chemical
Physical
Infectious
HOST

A person or other living animal, that
affords subsistence or lodgment to an
infectious agent under natural condition.
COMPONENTS OF HOST








The age
Sex
Genetic-Hereditary
Ethnic / race
Physiologic / Psychological status
Habit / tingkah laku
Immunologic status
The previous illnes
ENVIRONMENT

As the aggregate of all the external
conditions and influence affecting the
life and development of an organisme.
COMPONENTS OF
ENVIRONMENT



Physical environment : such as
Geographic, Geology, Climate
Biological environment : such as people,
flora, fauna ; population density, food
Socioeconomic, such as : income,
education, culture, urbanization,
economic growth, poverty, fertility etc.
CONSIDERATIONS FOR
CAUSATION

Temporal relation:


Plausibility


Does the removal of a possible cause lead to reduction of disease risk?
Study design


Is increased exposure to the possible cause associated with increased effect?
Reversibility


What is the strength of the association between the cause and the effect? (relative risk)
Dose-response relationship


Have similar results been show in other study?
Strength


Is the association consistent with the other knowledge? (MOA, evidence from
experimental animal)
Consistency


Does the cause precede the effect? (essential)
Is the evidence based in a strong study design?
Judging the evidence

How many lines of evidence lead to the conclusion?
TERMS IN DISEASE
THE INCUBATION PERIOD

The time interval between contact with an agent
and the first clinical evidence of resulting
disease .
It depends on :
 Portal of entry ( there is a defense mechanism)
 The ability of multiplication (infectivity).
 Number of agents
 Level of antibody in the host
It varies individually
Type of incubation period in the disease outbreak
A
B
A : skewed to the left, when the disease has a
short incubation period
B : skewed to the right, when the disease has a
longer incubation period
DEFENSE MECHANISM



THE ABILITY TO REACT AGAINST AGENT
INVASION IN THE BODY :
Consist of :
The external defense mechanism such as
physical and chemical reaction.
The internal defense mechanism : cellular
and humoral immunity
INTERLUDE
The lightwave travel not in straight singular
waveform. The further, the more curvature it
formed.
TYPES OF DISEASES


Communicable diseases
Chronic non communicable diseases
COMMUNICABLE DISEASES
The leading communicable diseases in the
world are:
1. Acute respiratory infections (3,76 millions)
2. HIV/AIDS (2,8 millions)
3. Diarrhoeal diseases (1,7 millions)
4. Tuberculosis (1,6 millions)
5. Malaria (1 million)
6. Measles (0,8 million)
COMMUNICABLE DISEASES
1.Directly, from other infected humans or
animals
2.Indirectly, through vectors, airborne particles
or vehicles
COMMUNICABLE DISEASES



Vectors: insects or animals that carry
infectious agents from person to person
Vehicles: contaminated objects or elements
of the environment
Contagious: ability to spread between
humans without intervening vector or vehicle
COMMUNICABLE DISEASES


Epidemics: the occurence of cases in excess
of what is normally expected in a community
or region
Endemic: the relatively stable pattern of
occurence in a given geographical area or
population group at relatively high prevalence
and incidence
COMMUNICABLE DISEASES
CHAIN OF INFECTION




The Infectious agent
The transmission process
The host
The environment
COMMUNICABLE DISEASES
THE INFECTIOUS AGENT
The factors determining the nature of the infection:
1.
Pathogenicity: The ability to produce a disease.
Measured by ratio number of persons whom
clinically ill compared to the exposed
2.
Virulence: The severity of disease
3.
Infective dose: The amount required to cause
infection in susceptible subjects
4.
Reservoir: The natural habitat
5.
Source of infection:The person or object from wich
the host acqures the agent
COMMUNICABLE DISEASES
THE TRANSMISSION PROCESS
1.
2.
Direct transmission
Indirect transmission
COMMUNICABLE DISEASES
THE HOST


Extremely vary between individuals
Determined by self-reaction to the agents
COMMUNICABLE DISEASES
ENVIRONMENT

Plays a critical role in the development of
communicable diseases
CHRONIC NON
COMMUNICABLE DISEASES
The leading chronic diseases in the world are:
1. CVD (17,5 million deaths)
2. Cancer (7,5 million deaths)
3. Chronic respiratory disease (4 million
deaths)
4. Diabetes (1,1 million deaths)
CHRONIC NON
COMMUNICABLE DISEASES
The underlying determinants of health and their
impact on chronic diseases
Socioeconomics,
Cultural, political &
Environmental
factors
Common
Modifiable & non
modifiable risk
factors
Intermediate
Risk factors
Main chronic
diseases
CHRONIC NON
COMMUNICABLE DISEASES
Levels of prevention:
1. Primordial prevention
2. Primary prevention
3. Secondary prevention
4. Tertiary prevention
Level
Phase
of
disease
Aim
Actions
Target
Primordial
Underlying
economic,
social,
environment
al conditions
leading to
causation
Establish
and maintain
conditions
that minimize
hazards to
health
Measures that inhibit the emergence
of environmental, economic, social and
behavioral conditions
Total population or
selected groups; achived
through public health
policy and health
promotion
Primary
Specific
causal
factors
Reduce the
incidence of
disease
Protection of health by personal and
communal efforts, such as enhancing
nutritional status, providing
immunization, and eliminating
environmental risks
Total population, selected
groups and healthy
individuals; achieved
through public health
policy
Secondary
Early stage
of disease
Reduce the
prevalence
of disease by
shortening
its duration
Measures available to individals and
communities for early detection nd
prompt intervention to control disease
and minimize disability (e.g. Through
screening programs)
Individuals at igh risk and
patients; achieved through
preventive medicine
Tertiary
Late stage of
disease
(treatment,
rehab)
Reduce the
number
and/or
impact of
complication
s
Measures aimed at softening the
impact of long-term disease and
disability; minimizing suffering;
maximizing potential years of useful
life
Patients; achieved through
rehabilitation
REFERENSI

Bonita, R., Beaglehole, R., Kjellstrom, T.
Basic epidemiology, 2nd ed. Geneva, World
Health Organization, 2006