Wednesday, 18 January 2012
Saturday, 14 January 2012
Immunity
Immunity |
Immunity
is the relative ability of the body to resist almost all types of organism or
toxins that tend to damage the tissues and organs.
Immunity
is also defined as the ability of the body to recognize, destroy and eliminate
the antigenic material foreign to its own. It is normally a defensive mechanism
of the body.
Antigen: An antigen is a substance which when
introduced into the system is capable of including an immune response leading
to the formation of antibody with which it reacts specifically.
Antibody:
An antibody is a modified globulin (immunoglobulin) produced in response to
an antigen with which it reacts specifically.
Immunization:
It is a technique by which immunizing agents are introduced into the
body for the production of antibody to prevent diseases.
Toxin: It is the product of bacterial
metabolism and is toxic, i.e., inhibitory or lethal to the cells of the host.
Toxin may
be –
(i)
endotoxin
(ii)
exotoxin
Toxoid: It
is a derivative of the toxin which is devoid of toxigenicity but
still possessing the antigenicity.Toxic are
used for the purpose of immunization.
Examples: Tetanus toxoids, diptheria toxoids
Classification
of immunity:
- Innate or nonspecific
- Genetic
- Mechanical
- Humoral
- Cellular
- Acquired or specific
a.Active
- Natural
- Artificial
b.Passive
- Natural
- Artificial
Cold chain:
Definition: Cold
chain is a system of storage and transport of vaccine at low temperature
maintaining their potency from the manufacturer to the actual vaccination site.
Usefulness: Cold
chain is necessary because vaccine failure may occur due to failure to store
and transport under strict temperature controls.
Expanded Programme on Immunization (EPI) / universal
child immunization
- Introduction
Ø In
May 1974, the WHO officially launched a global immunization programme, known as
‘Expanded Programme on Immunization’ (EPI) to protect all children of the world
against six vaccine preventable diseases, namely – diphtheria, whooping cough,
tetanus, polio, tuberculosis and measles by he year 2000.
Ø In
Bangladesh, EPI was formally launched on 7th April 1979. The
following Table shows the achievements and targets of EPI under 1 year in
Bangladesh.
- National
EPI Policies
- 1. To immunize all
children under one year of age throughout the country.
- 2. To immunize all women of child
bearing age including the pregnant women throughout the country.
- 3. To extend service delivery point up
to the community to cover all target population.
- 4. To involve community level health
and family planning workers as vaccination.
Table 14.13. National
EPI Vaccination Schedule:
Name
of the vaccine
|
Quantity
for each dose
|
Interval
between doses
|
Number
of doses
|
Time
of starting
|
Time
of complementation
|
BCG
|
0.05ml
|
1
|
After
birth
|
1
year
|
|
DPT
|
0.05ml
|
4
weeks
|
3
|
6
weeks
|
1year
|
HBV
|
0.05ml
|
4
weeks
|
3
|
6
weeks
|
|
OPV
|
0.05ml
|
4
weeks
|
4
|
6
weeks
|
1
year
|
Measles
|
0.05ml
|
1
|
After
270 days
|
1
year
|
- Vaccination should be completed within 1 year of age.
- The vaccine given before the interval between doses is uncountable and that dose of vaccine is valueless.
- Doses of OPV are 4. The 4th dose should be with measles vaccine.
- There is no maximum limit of days between intervals of doses. If there is delay in coming to take the scheduled dose of vaccine, the vaccination should be completed according to vaccination schedule.
Disinfection and disinfectants
- Disinfection is the killing of infectious agents outside the body by direct exposure to disinfectants.
- Disinfectants or germicide is a substance which destroys harmful microbes (not usually spores) present on the surface of inanimate objects.
- Sterilization is the process of destroying all living organism – pathogenic and non – pathogenic including their spores.
- Antiseptic is a substance which destroys or inhibits the growth of potentially infectious microorganisms.
- Disinfestations is the process of destroying small animals particularly arthropods or rodents.
Classification
of disinfectants:
- Natural
- Fresh air
- Sunlight
- Physical
- Heart
- Radiation
- Chemical
- Solid
- Liquid
- Gaseous
Saturday, 7 January 2012
Friday, 6 January 2012
DEMOGRAPHY
Demography |
Definition:
Demography
is the scientific study of human population.
Focus of Demography :
Demography
focuses its attention on three readily observable human phenomena :
(i) Changes in
population ‘size’ (growth or decline).
(ii) The ‘composition’
of the population and
(iii) the
‘distribution’ of population in space.
Demographic Cycle (transition)
The history
of world population since 1950 suggests that there is a demographic cycle of 5
stages through which a nation passes :
(I) First stage -
high stationary.
(ii) Second stage -
early expanding .
(iii) Third stage -
late expanding.
(iv) Fourth stage -
law stationary.
(v) Fifth stage-
declining.
Population Explosion :
“Population explosion”
means a rate more than a very rapid growth of population.
There is no
definite bench mark, it must be in relation to the resources of a particular
country. Opinion varies, some say it begins when growth crosses 2%, others say
it is when the growth reaches the rate of 2.5%.
Population Pyramid :
The
age of people of Bangladesh is typical of developing countries, with a broad base
and a tapering top, age group. This also indicates a rapid population growth in
future.
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