1. G ENERAL P RINCIPLES OF P REVENTION A ND C ONTROL OF C OMMUNICABLE D ISEASES

2. Prevention:- Measures applied on healthy person to prevent the diseases before their occurrence. Control:- Measures applied to avoid the spread of the diseases after their occurrence i.e. Reduce the incidence and / or the prevalence of these diseases.

3. General Principles of Prevention Successful prevention depends upon knowledge of causation and dynamics of disease transmission, identification of risk factors and risk groups and availability of prophylaxis or early detection and treatment.

4. Levels of prevention: It has become customary to define prevention in terms of three levels: Primary prevention. Secondary prevention. Tertiary prevention.

5. 1- P RIMARY PREVENTION. Actions taken prior to the onset of the disease which control the causation and the risk factors thus limit the incidence or prevent the possibility of occurrence of a disease. Example of primary prevention: Health education. Environmental sanitation. Nutritional interventions. Specific protection. Immunization. Chemoprophylaxis. Use of specific nutrients. Protection from carcinogens and allergens. Protection against accidents Protection against occupational hazards.

6. 2- S ECONDARY PREVENTION. Actions which hinder the progress of a disease at its early stage and prevent complications. The specific interventions are early diagnosis (e.g. Screening tests and case finding programs ) and adequate treatment before irreversible pathological changes have taken place. It may also, protect others in the community from acquiring the infection and thus provide at once secondary prevention for the infected individuals and primary prevention for their potential contacts. Secondary prevention is largely the domain of clinical medicine. The health programs initiated by governments are usually at the level of secondary prevention. Early diagnosis and treatment though not as effective and economical as primary prevention, it may be critically important in reducing the high morbidity and mortality in certain diseases such as essential hypertension, cancer cervix and breast cancer. An example of secondary prevention is mass treatment. A mass treatment is used in the control of certain diseases, e.g. Trachoma, malaria and bilharziasis. The rationale for a mass treatment program is the existence of at least four to five cases of latent (incubating) infection for each clinical case of active disease in the community. Patients with a latent infection may develop disease at any time. In such cases, mass treatment is a critical factor in the interruption of disease transmission.

7. 3- T ERTIARY PREVENTION : Actions taken when the disease process has advanced beyond its early stages i.e. intervention in late pathogenesis phase. The aim of tertiary prevention is : To limit impairments and disabilities. To decrease suffering. To promote the patient's adjustment to rehabilitation.

8. Rehabilitation:- It is a measure to train disable individuals to reach the highest level of functional ability by using combined coordinated medical, social and educational measures. Examples of rehabilitation:- Special schools for blind pupils. Provision of aids for crippled. Reconstructive surgery for leprotics. Modification of life for tuberculous or cardiac patients.

9. G ENERAL P RINCIPLES OF C ONTROL I - Measures applied to the agent: Sterilization and disinfections. II – Measures applied to the reservoir of infection: A) Measures applied to cases: 1- Case finding. 2- Reporting. 3- Isolation. 4- Treatment. B) Measures applied to carriers: 1- Detection. 2- Exclusion from work if affect the community. 3- Treatment for the carrier state. C) Measures applied to animal reservoir.

10. III - Measures applied to the contacts: 1- Enlistment. 2- Surveillance. 3- Isolation. 4- Increase resistance. 5- Health education IV - Measures applied to the environment: - Improving Sanitation.

11. V - M EASURES APPLIED TO THE HOST :. 1- Non-specific. 2- Specific

12. a) Non-specific measures: Health education. Good standard of nutrition. Provision of adequate housing. Provision of adequate recreation facilities. Provision of suitable working condition. Periodic selective examination. Personal hygiene. Protection against accidents. b) Specific measures: Use of specific passive and active immunization and Chemoprophylaxis.