Transcript Definitions - Dr Muhammad Razaq Malik

Department
Of
Community Medicine
DR. MUHAMMAD RAZZAQ MALIK
M.B.B.S, MCPS, (Com.Med)
Assistant Professor
(Deptt. of Com.Med)
Sheikh Zayed Medical College
Rahim Yar Khan.
DISEASE
A condition in which the body
health is impaired”.
A condition of the body or
some part or organ of body in
which
its
functions
are
disrupted or deranged.
ILLNESS
It is a phenomenon in which
one or more natural functions
of the body are so disturbed
that the affected individual
cannot meet the natural
requirements of everyday life.
INFECTION
INFECTION
It is a process of
introduction of microorganisms into
human host,
 followed by their multiplication within
the body at the expense of the host.
 The
microorganisms
may
be
protozoon, bacteria, viruses or
Richttsiae.
INFESTATION
INFESTATION
For persons or animals the
lodgment, development and
reproduction of arthropods
on the surface of the body
or in the clothing ,e.g. lice,
itch mite.
CONTAMINATION
• It is presence of an infectious agent on a
body surface; also on or in clothes,
beddings, toys, surgical instruments or
dressings, or other inanimate articles or
substances including water, milk and food.
Pollution
• It is the presence of offensive, but not
necessarily infectious matter in the
environment. Contamination on a body
surface does not imply a carrier state
•Types of diseases
• INFECTIOUS DISEASE
• CONTAGIOUS DISEASE:
• COMMUNICABLE DISEASE
• NON COMMUNICABLE DISEASE
INFECTIOUS DISEASE
It is a state of disorder that results
from an infection by microorganisms
bacteria or viruses and if the
secondary determinants favor the
occurrence of disease, e.g., cholera,
malaria, tuberculosis, dengue fever .
OPPORTUNISTIC INFECTION
Infection by an organism that is not
normally pathogenic, but can cause
disease if resistance is lowered.
. The organisms include Herpes
simplex, Cytomegalovirus,
Toxoplasmosis,
M. tuberculosis etc.
CONTAGIOUS DISEASE:
• A disease that is transmitted
through contact.
• Examples include scabies,
trachoma, STD and leprosy.
COMMUNICABLE DISEASE
An illness due to a specific
infectious agent or its toxic
products capable of being directly
or indirectly transmitted from man
to man, animal to animal, or from
the environment (through air,
dust, soil, water, food, etc.) to
man or animal
NON COMMUNICABLE DISEASE
• These are the diseases that are caused
not by any infectious agent but by the risk
factors. The most common risk factors are,
• Cigarette and other forms of smoking
• Alcohol Use
• Environmental Risk factors
• Life style changes
• Stress factors
EPIDEMIC DISEASE
(Epi – upon; demos people), The
“unusual” occurrence in a community
or region of disease, specific healthrelated behavior (e.g., smoking) or
other health-related events (e.g.,
traffic accidents) clearly in excess of
“expected occurrence”.
The key words in the definition of an
epidemic are: in excess of “expected
occurrence”.
ENDEMIC
(En=in; demos= people). It refers
to the presence of a disease or
infectious agent within a given
geographic area of population
group.
For instance, common cold is
endemic because somebody
always has one.
PANDEMIC
An epidemic usually affecting a
large proportion of the population,
occurring over a wide geographic
area such as a section of a
nation, the entire nation, a
continent or the world e.g.,
influenza pandemics of 1918 and
1957, cholera el tor in 1962 (still
continuing)
and
acute
hemorrhagic conjunctivitis in 1971
•Factors of
Disease
Causation
Epidemiological Triad
• The concept that disease causation is not
only due to germs but it is due to multiple
factors,
• Host
• Environment
• Agent
HOST
• Who can be the Host?
Host
• A person or other animals,
including birds and arthropods,
that affords subsistence or
lodgment to an infectious
agent under natural conditions.
Types of Host
• Obligate host
It means the only host, e.g., man in
measles and typhoid fever.
• Transport host
• These are the hosts in which the
organism remains alive but does not
undergo development .
• It acts as a carrier or transport host.
• Primary or definitive hosts;
• Hosts in which the parasite attains
maturity or passes its sexual stage .
• Secondary or intermediate hosts
• These are hosts in which the parasite is in
a larval or a sexual state .
• DYNAMICS OF DISEASE
TRANSMISSION
• Source/Reservoir
• Transmission Agent
• Host
Sources and Reservoir
• Source of infection
• It is defined as "the person, animal, object
or substance from which an infectious
agent passes or is disseminated to the
host" .
• Reservoir
• Any person, animal, arthropod, plant, soil
or substance (or combination of these) in
which an infectious agent lives and
multiplies.
Types
• The reservoir may be of three types :
• 1.
• 2.
• 3.
Human reservoir
Animal reservoir
Reservoir in non -living things
. Human reservoir
• CASES :
• A case is defined as "a person in the
population or study group identified as
having the particular disease, health
disorder or condition under investigation"
• term primary case refers to the first case
of a communicable disease introduced into
the population unit being studied.
Carrier
• It is as "an infected person or
animal that harbors a specific
infectious
agent
in
the
absence of discernible cfinicaf
disease and serves as a
potential source of infection for
others"
Classification
• Type
• (a) Incubatory, (b) Convalescent (c) Healthy
Duration
• (a) Temporary
• (b) Chronic
• Portal of Exit
• (a) Urinary
• (b) Intestinal
• (c) Respiratory
• (d) Others