concept of disease control and prevention.ppt

prevention of disease in community area

1. CONCEPT OF DISEASE
PREVENTION AND CONTROL
BY
Mr. Sanjay Gupta
Lecturer

2. INTRODUCTION:
Every disease has certain weak points
susceptible to attack.
The basic approach in controlling disease is to
identify these weak points and break the
weakest links in the chain of transmission.
This requires sound epidemiological
knowledge of the disease-that is its
magnitude,distribution in time,place and
person,multifactorial causation,sources of
infection and dynamics of disease transmission.

3. Disease control involves all the measures
designed to prevent or reduce as much as
possible the incidence,prevalence and
consequences of disease.
This includes community
participation,political support and
intersectoral co-ordination.
Control measures should not be delayed
because of incomplete or lack of accurate
knowledge of the etiological agent.

4. Broadly these are measures,results
of epidemiological investigation
1.the reservoir or the source of
infection
2.The routes of transmission
3.The susceptible host(people at
risk)

5. I.CONTROLLING THE RESERVOIR
The first link in the chain of
causation,the most desirable control
measure would be to eliminate the
reservoir or source,if that could be
possible.
The general measures of reservoir control
compromise:early
diagnosis,notification,isolation,treatment,q
uarantine,surveillance and disinfection-all
directed to reduce the quantity of the agent
available for dissemination.

6. 1.EARLY DIAGNOSIS
The first step in the control of a communicable
disease is its rapid identification.
.It has been aptly said that prompt detection of
cases and carriers and their treatment is like
stamping out the spark rather than calling the fire
brigade to put out the fire caused by the spark.
Frequently laboratory procedures may be
required to confirm the diagnosis.

7. 2.NOTIFICATION
Once an infectious disease has been detected
or even suspected it should be notified to the
local health authority,
Notification is an important source of
epidemiological information.it enables early
detection of disease out breaks,which permits
immediate action to be taken by the health
authority to control their spread.
Notification of infectious diseases is often
made by the attending physician or the head
of the family,but any one,including the lay
people can report,even on suspicion.
•

8. 3.EPIDEMIOLOGICAL
INVESTIGATIONS
An epidemiological investigation is called
for whenever there is a disease outbreak,
.Broadly,the investigation covers the
identification of the source of infection and
of the factors influencing its spread in the
community.
These may include geographic situation,climatic
condition,social,cultural and behavioural patterns
and more importantly the character of the
agent,reservoir,the vectors and vehicles,and the
susceptible host populations..

9. 4.ISOLATION
It is defined as “separation for the period
of communicability of infected persons or
animals from others in such places and
under such circumstances,as to prevent or
limit the direct or indirect transmission of
the infectious agent from those affected to
those who are susceptible,or who may
spread the agent to others”
The purpose of isolation is to protect the
community by preventing transfer of
infection from reservoir to the possible
susceptible hosts.

10. 5.TREATMENT
The object of treatment is to kill the infectious
agent when it is still in reservoir i.e before it is
disseminated.
Treatment reduces the communicability of
disease,cuts short the duration of illness and
prevents development of secondary cases.
Treatment can take the form of individual
treatment or mass treatment.In the latter
category,all the people in the community are
administered the drugs whether they have the
disease or not….(trachoma)

11. 6.QUARANTINE
Quarantine has been defined as “the limitation of
freedom of movement of such well persons or
domestic animals exposed to communicable
disease for a period of time not longer than the
longest usual incubation period of the disease,in
such a manner as to prevent effective contact
with those not so exposed.”.
quarantine measures are also “applied by a health
authority to a ship,an aircraft,a train,road
vehicle,other means of transport container,to
prevent the spread of disease,reservoirs of disease
or vectors of disease.”

12. II. INTERRUPTION OF
TRANSMISSION
A major aspect of communicable disease control
relates to “breaking the chain of transmission”or
interruption of transmission.
This may mean changing some components of
man’s environment to prevent the infective agent
from a patient or carrier from entering the body
of susceptible person
.For example,water can be a medium for the
transmission of many disease such as
typhoid,dysentery,hepatitis A ,cholera and
gastroenteritis.

13. III.THE SUSCEPTIBLE HOST
•A.immunization:
•One effective way of controlling the spread
of infection is to strengthen the host
defenses.
•Under certain circumstances this may be
accomplished by active
immunization,which is one of the most
powerful and cost-effective weapons of
modern medicine.there are some infectious
diseases whose control is solely based on
active immunization,e.g.Polio,tetanus,
,and measles.

14. •A well-thought-out immunization
schedule must be (a)epidemiologically
relevant,that is,vaccinations should be
included only against diseases which
are public health problems and against
which an effective vaccine exists.

15. •(b)immunologically effective:
•children must be vaccinated at an age
when they can benefit from
it,i.e.,when they are capable of
forming defenses and when they have
lost the antibodies transmitted by the
mother,above all children must be
vaccinated at the right time,that is
before they are exposed to possible
infection.an immunization may not be
effective if given within too short an
interval between subsequent doses.

16. •©socially acceptable:
•the schedule must take into account
the local customs,beliefs and
practices,seasonal and climatic factors
and daily work pattern of the
community.
•one important factor is to reduce long
waiting time for patients whose sole
purpose in visiting the clinic was to be
immunized.

17. 2.PASSIVE IMMUNIZATION
Three types of preparations are available for passive
immunity-(a)normal human immunoglobulin
•(b)specific human immunoglobulin,and(c)antis
era or anti-toxins
•passive immunization is a short term expedient
useful only when exposure to infection has just
occurred or is imminent within the next few
days.the duration of immunity induced is short
and variable(1-6 weeks)undesirable reactions
may occur especially if anti serum is not of
human origin.

18. 3.COMBINED PASSIVE AND ACTIVE
IMMUNIZATION:
•In some iseases(tetanus,diphtheria,rabies)passive
immunization is often undertaken in conjugation
with inactivated vaccine products,to provide both
immediate passive immunity and slowly
developing active immunity
•According to the current recommendations
immunoglobulins should not be given within 3
weeks before or until 2 weeks after
administration of a live attenuated vaccine.
•for e.g the antibody response to live attenuated
measles vaccine is diminished in persons who
receive immunoglobulin concurrently.

19. 4.CHEMOPROPHYLAXIS
•Chemo prophylaxis implies the protection
from,or prevention of disease.this may be
achieved by causal prophylaxis or clinical
prophylaxis:
•-causal prophylaxis implies the complete
prevention of infection by the early elimination
of the invading or migrating causal agent.for
example,there is no causal prophylaxis available
against malaria.
•-clinical prophylaxis:implies the prevention of
clinical symptoms;it does not necessarily mean
elimination of infection.

20. 5.NON SPECIFIC MEASURES
Most of the non specific measures to interrupt
pathways of transmission are of general
applicability
.Improvements in the quality of life(better
housing,water supply,sanitation,nutrition
education()fall into this category.
Non specific measures will also include”legislative
measures”wherever needed,to formulate
integrated programme and permit effective
programme implementation
.

21. Another important non specific measure is
community involvement in disease
surveillance,disease control and other activities.
•Health education remains the only approach to
enlist public co-operation and induce relevant
changes in the behaviour and life styles of
people.
•Surveillance can provide the health agencies with
an overall intelligence and disease accounting
capability.surveillance is an essential prerequisite
to the rational designing and evaluation of any
disease control programme.
•
•