concept of prevention, concept of control, elimination, eradication & iceberg phenomenon for medical student teaching

1. CONCEPT OF PREVENTION
Dr. Madhusudan Swarnkar
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2. • what is the importance of sequences of action in the
natural history of a disease?
• The importance is that it serves as the basis of
planning the preventive activities.
• In fact, we take preventive actions throughout the entire
sequence of the natural history of the disease.
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3. Goals of Preventive medicine
are
• to promote health,
• to preserve health,
• to restore health when it is impaired,
• prolong life and minimize suffering by preventing the
suffering of disease.
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4. Prevention
• Actions eradicating, eliminating or minimizing the
impact of disease and disability,
• or
• if none of these are feasible, retarding the progress of
the disease and disability.
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5. Levels of Prevention
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Stage of disease Level of prevention Type of response
Pre-disease Primary Prevention Health promotion and
Specific protection
Latent Disease Secondary prevention Pre-symptomatic
Diagnosis and
treatment
Symptomatic Disease Tertiary prevention •Disability limitation for
early symptomatic disease
•Rehabilitation for late
Symptomatic disease
There are four major levels of prevention, depending on the phase of the
natural history of the disease :

6. Primordial prevention
• It consists of measures that inhibit the emergence of risk
factors in the form of environmental, economic, social, and
behavioral conditions and cultural patterns of living etc.
• It is the prevention of the emergence or development of risk
factors in which they have not yet appeared.
• For example, many adult health problems (e.g., obesity,
hypertension) have their early origins in childhood, because
this is the time when lifestyles are formed (for example,
smoking, eating patterns, physical exercise).
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7. Primordial prevention (cont.)
• In primordial prevention, efforts are directed
towards discouraging children from adopting
harmful lifestyles
• The main intervention in primordial prevention is
through individual and mass education
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8. Health Promotion
The process of enabling people to increase control over, and to
improve health
Interventions in this area are:
1. Health Education
2. Environmental Modifications eg: safe water, sanitary
latrines, control of insects and improvement of housing.
3. Nutritional interventions- comprise food distribution and
nutrition improvement of susceptible group. eg; child
feeding programmes, food fortification, nutritional education
etc
4. Lifestyle & Behavioral changes
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9. Health Promotion
• It include all steps undertaken to improve the level of general
health and well being so that conditions for initiation of disease
process are prevented.
• these steps are not specific for any disease or a group of
diseases.
• These actions include
• improvement in the overall socio-economic status of the population,
• health education on personal and oral hygiene,
• feeding programmes for mothers and children,
• Promotion of breast feeding,
• Promotion of small family norms,
• Education and motivation for healthy lifestyle
• Genetic counseling (premarital and marriage counseling)
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10. Primary Prevention
• These are all measures of prevention that are
undertaken during the phase of pre-pathogenesis
(phase of susceptibility), before the disease process
has started.
• Primary prevention involves two sub-steps:
• Health Promotion and
• Specific Protection
• Both steps are undertaken during the stage of
susceptibility (pre-pathogenesis), to avert the
initiation of the disease process.
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11. Primary Prevention
• Health promotional approach improves the general health so that
a number of diseases are aimed at not a single disease, from
preventive point of view.
• Eg. when we promote breast feeding among children, we are
trying to prevent general malnutrition, vitamin A deficiency,
providing antibodies against various diseases, preventing
diarrheal diseases (because artificial feeding carries the risk of
infection) and so on.
• On the other hand when condom is used, it is for a very specific
group of diseases i.e. STDs; when measles vaccine is given it is
for a specific disease viz. measles.
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12. Specific Protection
• These include measures to prevent the initiation of specific
diseases or a group of diseases.
Examples
• immunization against vaccine preventable diseases,
• fortification of foods with specific nutrients (as salt with iodine),
• use of condoms to protect against sexually transmitted diseases
(STDs) and HIV,
• use of chemoprophylactic drugs to protect against particular
diseases (as malaria, meningococcal meningitis, plague,
tuberculosis, leptospirosis, etc),
• use of helmets to protect against head injuries, etc.
• Use of insecticide treated bed-nets
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13. Secondary Prevention
• include all actions undertaken at early pathogenesis stage
(asymptomatic disease) to halt the progress of disease at it’s
earliest or incipient stage, by “early diagnosis and prompt
treatment”.
• It is like stamping off a fire when it has just started rather than
call the fire brigade after the fire has become voluminous.
• The person is not aware of any signs or symptoms and the
routine clinical methods also may not be able to detect a disease
at this stage, since the disease process is in the very preliminary
stage.
• The classical example of this level of prevention is “screening for
disease” as for breast cancer (using mammography) and
cervical cancer (using pap smear).
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14. Early diagnosis and treatment
• Helps in recovery from disease(restoration)
• Reduce the duration of illness in the individual
• Minimize the suffering
• Prevents the development of complications
• Prevents further spread of disease in community
• Prevents or postpones the death of the individual
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15. Tertiary Prevention
• all measures undertaken when the disease has
become clinically manifest or advanced,
• to prevent or delay death,
• reduce or limit the impairments and disabilities,
• minimize suffering and
• to promote the subject’s adjustment to irremediable conditions
• Tertiary prevention has two types of approaches
• disability limitation and
• rehabilitation.
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16. Disability Limitation :
• These include all measures to prevent the occurrence of
further complications, impairments, disabilities and
handicaps or even death.
• Examples:
• When we apply plaster cast to a patient who has suffered Colle’s
fracture, we are actually trying to prevent complications and
further disability like mal-union or non-union.
• When we give complete rest, morphine, oxygen and
streptokinase to a patient of Acute MI, we are actually trying to
prevent death or complications like arrhythmias / CHF.
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17. • Disease : This is a pathological process and it’s manifestations
which indicate a departure from the state of perfect health.
• Impairment is “any loss or abnormality of psychological,
physiological or anatomical structure or function.”
• Disability is “any restriction or lack of ability to perform an activity
in the manner or within the range considered normal for the
human being.”
• Handicap is termed as “a disadvantage for a given individual,
resulting from an impairment or disability, that limits or prevents
the fulfillment of a role in the community that is normal for that
individual (depending on age, sex, and social and cultural
factors).”
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18. Disability limitation
Disease Impairment
(Accident) (Loss of foot)
Disability (Can’t walk)
Unemployed
(Handicap)
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19. • For example,
• an agricultural worker gets acute myocardial infarction. This is
the disease.
• Because of this disease, he would have inadequacy in the
pumping action of the heart with a compromise in the
oxygenation of the blood. These are the “impairments” due to the
disease.
• Due to these impairments he will not be able to undertake hard
manual labour, which an otherwise healthy male of his age
would have undertaken - this is the disability, resultant to the
impairment.
• Finally because of this disability, he will lose his job of an
agricultural worker and hence not able to earn adequate
livelihood - this is the handicap, consequent to the disability.
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20. Rehabilitation :
• “Rehabilitation” (Re =restore into, habitat = the original home or
environment of the person).
• Rehabilitation is the combined and coordinated usage of all the
available medical, social, educational and vocational measures,
for training and retraining the person to the highest level of
functional ability.
• It emphasizes that the duty and obligation of a Doctor who cares
for a patient does not end simply by curing the patient.
• It is also an obligation to assist the patient in getting rehabilitated
so hat he/she gets fully adjusted in the family and social
environment and lives a happy and productive life.
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21. Rehabilitation
• The combined & coordinated use of medical, social,
educational, psychological and vocational measures for
training & retraining the individual to the highest possible level
of functional ability.
• Identify the remaining capacities in individual and adopt
measures to make him fit independent, productive, useful and
active member in family and community
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22. Dimensions of Rehabilitation
• Medical rehabilitation : This is done by medical/surgical
procedures to restore the anatomy, anatomical and physiological
functions to as near normal as possible.
• Vocational rehabilitation : This includes training and education so
as to enable the person to earn a livelihood.
• Social rehabilitation : This involves steps for restoration of the
family and social relationships.
• Emotional and Psychological rehabilitation : This involves steps
to restore the confidence, and personal dignity
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23. Modes of Interventions
• Intervention- any attempt to intervene or interrupt the
usual sequence in the development of disease.
• This may be by the provision of treatment, education,
help or social support.
• Health promotion
• Specific protection
• Early Diagnosis and Treatment
• Disability limitation
• Rehabilitation
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24. Disease control
• In this disease agent is permitted to persist in the
community at a level where it ceases to be a public health
problem according to tolerance of the local population.
• It is a state of equilibrium established b/w agent, host, and
environmental components of disease process. Eg.
malaria control
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25. Aims
• Reducing the incidence of disease
• Reducing the duration of disease as well risk of
transmission eg. tubercuolsis, leprosy
• Reducing the effects of infection(physical and
psychosocaial)
• Reducing the financial burden to the community
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26. • Control activities focus on primary prevention or
secondary prevention, but most programs combine both.
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control
elimination
eradication

27. Disease Elimination
• Also known as regional elimiantion
• Intruption of transmission of disease from large geographic
region/areas Or
• reduction of disease to zero without total removal of
infectious agent
• Eg. elimination of measles, polio, diptheria, guneaworm.
• It is an imp. precurssor of eradication.
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28. Disease Eradication
• Tear out by roots.
• Termination of all transmission of infection by extermination
of the infectious agent.
• It is all or none phenomenon.
• This imply that infectious agent as well as disease has also
been completely reduced to zero
• Till now only Smallpox has been eradicated.
• It is an absolute process not a relative goal. Three diseases
are entrant for global eradication in near future.
• Polio
• Measles
• Dracunculosis/Guinea worm
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29. Evaluation of Control
• It is the process by which results are compared with
intended objectives or
• Simply the assesment of how well a programme is
performing
• It should always be considerd during the planning and
implementation stages of programme or activity
• It can also be useful in identifying performance difficulties
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30. The Iceberg of disease
Symptomatic disease
(what the physician sees)
- - - - - - - - - - - - - - - - - - -carriers, undiagnosed
--------------------------------What the physician- -
- - - - - - - - - - - - ---- -does not see -- - -- -
- - -- - - - - - -- - - - ---- ---latent, inapparent- - --
-- - -- - - -- - -- - - - - - - - - - pre-symptomatic
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31. • 1. Fortification of foods with specific nutrients as salt with iodine,
is an example of :
• (a) Primordial prevention (b) Primary prevention
• (c) Secondary prevention (d) Tertiary Prevention
• 2. Primary Preventive measure can be applied at which stage of
the natural history of disease :
• (a) stage of positive health (b) asymptomatic (early pathogenesis)
• (c) early, discernible disease (d) full - blown (classical) disease
• 3. Use of chemoprophylactic drugs to protect against malaria is
• (a) Primordial prevention (b) Primary prevention
• (c) Secondary prevention (d) Tertiary Prevention
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32. • 1. Education and motivation for healthy lifestyle is :
• (a) Primordial prevention (b) Secondary prevention
• (c) Health Promotion (d) Specific Protection
• 2. The inability to carry out certain function or activity which is
otherwise expected for that age / sex is known as :
• (a) Disease (b) Impairment (c) Disability (d) Handicap
• 3. Disability Limitation is part of :
• (a) Primordial prevention (b) Primary prevention
• (c) Secondary prevention (d) Tertiary Prevention
• 4. Screening for breast cancer using mammography is :
• (a) Primordial prevention (b) Primary prevention
• (c) Secondary prevention (d) Tertiary Prevention
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33. Quiz
• Match the following statements.
• Each option may be selected once, more than once, or not at
all:
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performing carotid endarterectomy in a
patient with transient ischemic attack
primary prevention
recommending regular physical activity to
a patient with no known medical problem
Secondary
prevention
vaccinating a health care worker against
hepatitis B
Tertiary prevention
giving isoniazid for 1 yr to a 28-year-old
medical student with a positive tuberculin
skin test.
Health promotion

34. Thanks
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