Concept of Preventing of Diseases

Concept of Prevention of Diseases

The goals of health care are to promote health, to preserve health, to restore health when it is impaired, and minimize suffering and distress. These are embodied in the word “prevention”. Successful prevention depends upon knowledge of causation, dynamics of transmission, identification of risk factors and risk groups, availability of prophylactic or early detection of risk factors and risk groups, availability of prophylactic or early detection and treatment measures. It is not necessary (although desirable) to know everything about the natural history of a disease to initiate preventive measures. Often times, removal or elimination of a single known essential cause may be sufficient to prevent a disease. The objective of preventive health care is to intercept or oppose the “cause” and thereby the disease process.

 Levels of Prevention

In modern days, the concept of prevention has become broad-based. It has become customary to define prevention in terms of four levels:

a.                 Primordial prevention

b.                Primary Prevention

c.                Secondary prevention

d.               Tertiary prevention

A.     primordial Prevention

This is primary prevention in its purest sense, that is, prevention of the emergence or development of risk factors in countries or population groups in which they have not yet appeared. For example, many adults’ health problems (e.g., obesity, hypertension) have their early origins in childhood, because this is the time when lifestyle formed (for example, smoking, eating patterns, physical exercise). 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.

 B.     Primary prevention

Primary prevention can be defined as “action taken prior to the onset disease, which removes the possibility that a disease will ever occur”. It signifies intervention in the pre-pathogenesis phase of disease or health. Primary prevention may be accomplished by measures designed to promote general health and well-being, and quality of life of people or by specific protective measures. Primary prevention is far more than averting the occurrence of a disease and prolonging life. It concludes the concept of “positive health”, a concept that encourages achievement and maintenance of “an acceptable level of health that will enable every individual to lead a socially and economically productive life”. It concerns individual’s attitude towards life and health and the initiative he takes about positive responsibility measures for himself, his family and his community. The concept of primary prevention is now being applied to the prevention of chronic diseases such as coronary heart disease, hypertension and cancer based on elimination or modification of “risk factors” of disease. The WHO has recommended the following approaches for primary prevention of chronic disease where the risk factors are established:


1.      POPULATION (MASS) STRATEGY: Another preventive approach is “population strategy” which is directed at the whole population irrespective of individual risk levels. For example, studies have shown that even a small reduction in the average blood pressure or serum cholesterol of a population would produce a larger reduction in the incidence of cardiovascular disease.


2. HIGH-RISK STRATEGY: the high-risk strategy aims to bring preventive care to individuals at special risk. This requires detection of individuals at high risk by the optimum use of clinical methods.


Primary prevention is a desirable goal. It is worthwhile to recall the fact that the industrialized countries succeed in eliminating a number of communicable diseases like cholera, typhoid and dysentery and controlling several others like plague, leprosy and tuberculosis, not by medical interventions but mainly by raising the standard of living (primary prevention). And much of these success came even before immunization became universal routine. To have an impact on the population, all the above three approaches (primary prevention, population strategy and high-risk strategy) should be implemented as they are usually complementary.

C.     Secondary Prevention

Secondary prevention can be defined as “action which halts the progress of a disease at its incipient stage and prevents complications”. By diagnosis and adequate treatment, secondary prevention attempts to arrest the disease and treating it before irreversible pathological changes have taken place; and reverse communicability of infectious diseases. It may also protect others in the community from acquiring the infection and thus provide at once secondary prevention. The health programmes initiated by governments are usually at the level of secondary prevention. The drawback of secondary prevention is that patient has already been subject to mental anguish, physical pain; and the community to loss of productivity. Secondary prevention is an imperfect tool in the control of transmission of disease. It is often more expensive and less effective than primary prevention. In the long run, human health, happiness and useful longevity will be achieved at far less expense with less stuffing trough primary prevention than through secondary prevention.


D.     Tertiary Prevention

When the disease process has advanced beyond its early stages, it is still possible to accomplish prevention by what might be called “tertiary prevention”. It signifies intervention in the late pathogenesis phase. Tertiary prevention can be defined as “all measures available to reduce or limit impairments and disabilities, minimize suffering caused by existing departures from good health and to promote the patient’s adjustment to irremediable conditions”. For example, treatment, even if undertaken late in the natural history of disease may prevent sequel and limit disability. When defect and disability are more or less stable, rehabilitation may pay a preventable, vocational, and medical components based on team work from a variety of professions.


Modes of Intervention

Modes of Intervention

Intervention:  Can see as any attempt to intervene or interrupt the usual sequence in the development of disease in man. This may be by the provision of treatment, education, help or social support. Five modes of intervention have been described which form a continuum corresponding to the natural history of any disease. These levels are related to agent, host and environment. They are:

·       Health Promotion

·       Specific protection

·       Early diagnosis and treatment

·       Disability limitation

·       Rehabilitation

A.     Health Promotion

Health promotion is “the process of enabling people to increase control over and to improve health”. It is not directed against any particular disease, but is intended to strengthen the host through a variety of approaches (interventions). The well-known interventions in this area are:

1.     HEALTH EDUCATION: This is one of the most cost-effective interventions. A large number of diseases could be prevented with little or no medical intervention if people were adequately informed about them and if they were encourage taking necessary precautions in time. Recognizing this truth, the WHO constitution states that “the extension to all people of the benefits of medical, psychological and related knowledge is essential to the fullest attainment of health”. The targets for education efforts many provides, community leaders and decision makers.

2.     ENVIRONMENTAL MODIFICATIONS: A comprehensive approach to health promotion requires environmental modifications, such as provision of safe water; installation of sanitary latrines; control of insects and rodents; improvement of housing, etc. it has been shown that many infectious diseases have been successfully controlled in Western countries through environmental modifications, even prior to the development of specific vaccines or chemotherapeutic drugs. Environmental interventions are non-clinic and do not involve the physicians.

3.   NUTRITIONAL INTERVENTIONS: these comprise of food distribution and nutrition improvement of vulnerable groups; child feeding programmes; food fortifications; nutrition education, etc.

4.    LIFESTYLE AND BEHAVIORAL CHANGES: the conventional public health measures or interventions have not been successful in making inroads into lifestyle reforms. The action of prevention in case, is one of individual and community responsibility for health, the physician and in fact each health worker acting as an educator than a therapist. Health education is a basic element of all health activity. It is of paramount importance in changing the views, behavior and habits of people.

B.     Specific Protection:

To avoid disease altogether is the ideal but this is possible in a limited number of cases. The following are some of the currently available interventions aimed specified protection:

a.      Immunization

b.      Uses of specific nutrient

c.      Chemo prophylaxis

d.      Protection against occupation hazards

e.      Protection against accident

f.       Protection from carcinogens

g.      Avoidance of allergens

h.      Control of specific hazards in general environment e.g, air pollution, noise control.

f.       Control of consumers product quality and safety of food drugs, cosmetics, etc.


C.     Early diagnosis and treatment:

EARLY DIAGNOSIS AND TREATMENT: Is defined as the detection of disturbance of homeostatic and compensatory mechanism while biochemical morphological, functions changes are still reversible. “Thus, in order to prevent overt disease or disablement, the criteria of diagnosis should, if possible, be based on biochemical, morphological and functional changes that precede the occurrence of manifested signs and symptoms”. This is of particular importance in chronic disease.


1.      EARLY DETECTION AND TREATMENT: are the main interventions of disease control. The earlier a disease is diagnosed, and treated the better it is from a point of view of prognosis and preventing the occurrence of further cases (secondary cases) or any long term disability. It is like stamping out the “spark” rather than calling the fire bridge to put out the fire. Strictly speaking, early diagnosis and treatment cannot be called prevention because the disease has already commended in the host. However, since early diagnosis and treatment interrupt the disease process, it has been included in the scheme of prevention, in as much as the goal of prevention is “to oppose or interrupt a cause to prevent or dissipate its effect.” Early diagnosis and treatment although not as effective and economical, as “primary prevention” may be critically important in reducing the high morbidity and mortality in certain diseases such as essential hypertension, cancer of the cervix and breast cancer. For many others such as tuberculosis, leprosy and STD early diagnosis and treatment bare the only effective mode to intervention. Early effective therapy has made it possible to shorten considerably the period of communicability and reduce the mortality from acute communicable diseases.

2.      MASS TREATMENT: A mass treatment approach is used in the control of certain diseases, Viz, Yaws, trachoma and malaria. The rationale for a mass treatment program is the exercise of at least 4-5 cases of latent infection for each clinical case of a active disease in the community. Patients with at latent (incubating) infection may develop disease at any time. In such case, mass treatment is a critical factor in the interruption of disease transmission. There are many variants of mass treatment-total mass treatment, juvenile mass treatment, selective mass treatment, depending upon the nature and prevalent of disease in the community.


C.     Disability limitation:

 When a patient reports late in the pathogenesis phase, the mode of intervention is disability limitation. The objective of this Intervention is to prevent or halt the transition of the disease process form impatient to handicap.


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