25/12/2010dr. salwa tayel1. 25/12/2010dr. salwa tayel2 associate professor family and community...

25/12/201025/12/2010 Dr. Salwa TayelDr. Salwa Tayel 11


Associate Professor Associate Professor Family and Community Medicine DepartmentFamily and Community Medicine Department

King Saud UniversityKing Saud University

ByBy

General Principles of Prevention ofGeneral Principles of Prevention of Infectious DiseaseInfectious Disease

Learning Objectives:Learning Objectives:

Identify the levels of prevention of infectious Identify the levels of prevention of infectious

diseases and tools for intervention at each level.diseases and tools for intervention at each level.

Describe the specific control measures for Describe the specific control measures for

infectious diseasesinfectious diseases



Levels of prevention:

1. Primary prevention.

2. Secondary prevention.

3. Tertiary prevention.

Levels of PreventionLevels of Prevention

• • Primary prevention => pre-event Primary prevention => pre-event phasephase

• • Secondary prevention => event phaseSecondary prevention => event phase

• • Tertiary prevention => post-event Tertiary prevention => post-event phasephase

Promotion (1ry prevention)Promotion (1ry prevention)

Early detection & care (2ry prevention)Early detection & care (2ry prevention)

Rehabilitation (3ry prevention)Rehabilitation (3ry prevention)25/12/201025/12/2010 Dr. Salwa TayelDr. Salwa Tayel 55


Tertiary Tertiary PreventionPrevention

Primary Primary PreventionPrevention

Secondary Secondary PreventionPrevention


I- Primary Prevention:

Actions taken prior to the onset of the disease

which aim to remove the possibility that a disease

will ever occur”

It limits the incidence of diseases by preventing

healthy people from developing disease.

Tools for intervention include:

A. Health promotion

B. Specific protection

A. Health promotion

It is intended to improve the general health It is intended to improve the general health

of the individual and community, through:of the individual and community, through:

1.1. Adequate nutritionAdequate nutrition

2.2. Environmental sanitationEnvironmental sanitation

3.3. Personal hygienePersonal hygiene

4.4. Health educationHealth education

5.5. Socio-economic developmentSocio-economic development

6.6. Genetic counseling … etc.Genetic counseling … etc.


B. Specific Protection is achieved

through:

1. Specific immunizations.

2. Chemoprophylaxis.


II- Secondary Prevention:II- Secondary Prevention:

Actions that Actions that detect and treat disease at an early detect and treat disease at an early

stagestage thus hinder the progress of a disease and thus hinder the progress of a disease and

prevent complicationsprevent complications. . i.e. intervention in i.e. intervention in early early

pathogenesis pathogenesis phase.phase.

The methods (tools) employed for early The methods (tools) employed for early

diagnosis are:diagnosis are:

1. Screening for sub-clinical disease, either in 1. Screening for sub-clinical disease, either in

screening surveys or in periodic medical screening surveys or in periodic medical

examinations.examinations.

2. Case finding (individual and community).2. Case finding (individual and community).25/12/201025/12/2010 Dr. Salwa TayelDr. Salwa Tayel 1010


III- Tertiary 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 disability and

prevent further complications or death.

Tools for tertiary prevention include rehabilitation

Rehabilitation:

It is a measure to train disable individuals

to reach the highest level of functional

ability by using combined coordinated

medical, social, vocational, psychological

and educational measures.


Rehabilitation comprises:1. Medical rehabilitation – restoration of

function or physical loss.2. Educational rehabilitation change of

educational methods.3. Vocational (occupational) rehabilitation

– restoration of the capacity to earn a livelihood.

4. Social rehabilitation: restoration of family and social relationships.

5. Psychological rehabilitation: restoration of personal confidence.25/12/201025/12/2010 Dr. Salwa TayelDr. Salwa Tayel 1313


Examples of rehabilitation:

1. Special schools for blind pupils.

2. Provision of aids for crippled.

3. Reconstructive surgery for leprotics.

4. Modification of life for tuberculous or cardiac

patients.


SummarySummaryEE


Factors affecting choice of appropriate prevention and

control measures:

It depends upon the knowledge of:

• causation and dynamics of disease transmission,

• identification of risk factors and high risk groups

• availability of tools of intervention (vaccine

chemoprophylaxis or treatment,..)

In general, control measures should be directed towards

the link in the infection chain is most susceptible to

interference.

Specific Control MeasuresSpecific Control Measures

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Agent

M.O.

T

HOST

Environment

The cycle of infection has three major links:The cycle of infection has three major links:

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Agent

M.O.T

HOST

Environment

Source- Disinfection -Sterilization

Reservoir-Isolation -Treatment- Detection of carriers - Control of animals

-Immunization-Chemoprophylaxis

-Vector control.-Snail control.

-Environmental sanitation

Measures Directed to the Measures Directed to the ReservoirReservoirMeasures applied to cases Measures applied to cases Case finding (early diagnosis)Case finding (early diagnosis) ReportingReporting IsolationIsolation Treatment (Chemotherapy)Treatment (Chemotherapy) Disinfection of contaminated objects with Disinfection of contaminated objects with

appropriate “enteric precautions,” appropriate “enteric precautions,” “respiratory precautions,” “universal “respiratory precautions,” “universal precautions” precautions”


Isolation is separation of infected persons from those not infected for the period of communicability.

Isolation is of decreasing value because: in-apparent infection may be large proportion, maximal infectivity may occur during the

early stages, carriers of infective agents may go

undetected, or many mild cases of infection spread disease

without being detected25/12/201025/12/2010 Dr. Salwa TayelDr. Salwa Tayel 2121

Measures applied to carriersMeasures applied to carriers1.1. Detection of carriers: It is important Detection of carriers: It is important

in certain diseases e.g. Enteric in certain diseases e.g. Enteric fever. fever.

2.2. Exclusion from work: in certain Exclusion from work: in certain occupations for example; occupations for example; – food handler (e.g. Typhoid carrier) or afood handler (e.g. Typhoid carrier) or a

– teacher (e.g. Diphtheria carrier).teacher (e.g. Diphtheria carrier).

3.3. Treatment for the carrier state.Treatment for the carrier state.


Measures applied to animal reservoir

Destruction of infected animals (in rabies,

plague) Inspection or slaughtering (in bovine

tuberculosis) Testing and Immunization (in brucellosis)

Careful husbandry and sterilization of animal

products (in anthrax).


Measures to Interrupt the Transmission of Organisms

Environmental Measures to prevent transmission of Environmental Measures to prevent transmission of

diseases by Ingestion of contaminated diseases by Ingestion of contaminated vehiclesvehicles

include:include:

Purification of waterPurification of water

Pasteurization of milkPasteurization of milk

Inspection of food handlers & public food placesInspection of food handlers & public food places

Improvements in housing conditions, andImprovements in housing conditions, and

Educating people in proper personal hygiene and hand Educating people in proper personal hygiene and hand

washingwashing..


Measures Reduce transmission of respiratory infection:

Proper ventilation of public places & classrooms,

Minimize close person to person contact (reduce overcrowding)

Control of dust.


Measures to reduce transmission of arthropod borne infections

Measures to control (reduce or Measures to control (reduce or eradicate) the vector include:eradicate) the vector include:

biological biological mechanical and mechanical and chemical methodschemical methods


Measures to reduce host Measures to reduce host susceptibility susceptibility

Measures to improve the defense mechanism of the host by using proper Chemoprophylaxis, immune-prophylaxis or Vaccination.



a) Chemoprophylaxisa) Chemoprophylaxis: Is the administration of chemicals : Is the administration of chemicals

including antibiotics, to prevent the development of an including antibiotics, to prevent the development of an

infection or the progression of an infection to active manifest infection or the progression of an infection to active manifest

disease.disease. e.g. e.g.

1.1. IsoniazidIsoniazid (INH) for contacts of (INH) for contacts of tuberculoustuberculous patients. patients.

2.2. RifampicinRifampicin for contacts of for contacts of meningeococcalmeningeococcal meningitis.meningitis.

3.3. ChloroquineChloroquine for travelers to for travelers to malariamalaria areas. areas.

b) Ib) Immune-prophylaxis (Passive immunization): Passive immunization): anti-diphtheritic anti-diphtheritic

serum.serum.

Acquired immunityAcquired immunity


VaccinationVaccination

Vaccines protect against disease by Vaccines protect against disease by inducing immunity. They are widely and inducing immunity. They are widely and routinely administered around the world. routinely administered around the world.

Expanded Programme on Immunization Expanded Programme on Immunization (EPI) was initiated in 1974(EPI) was initiated in 1974

It is estimated that over 2.5 million deaths It is estimated that over 2.5 million deaths are prevented through vaccination every are prevented through vaccination every year.year.


Criteria for effective VaccinesCriteria for effective Vaccines

Should meet the quality requirements of WHO policy Should meet the quality requirements of WHO policy on vaccine quality. on vaccine quality.

Be safe and have a significant impact in all target Be safe and have a significant impact in all target populations. populations.

Be easily adapted to the schedules and timing of the Be easily adapted to the schedules and timing of the national childhood immunization service. national childhood immunization service.

Not interfere significantly with the immune response Not interfere significantly with the immune response to other vaccines given simultaneously. to other vaccines given simultaneously.

Be formulated to meet common technical limitations, Be formulated to meet common technical limitations, e.g. in terms of refrigeration and storage capacity.e.g. in terms of refrigeration and storage capacity.


Benefits of immunizationBenefits of immunization

Immunization is a proven tool for controlling Immunization is a proven tool for controlling and even eradicating infectious diseases. and even eradicating infectious diseases.

Through vaccination Smallpox was Through vaccination Smallpox was eradicated eradicated

Poliomyelitis has been eliminated from Poliomyelitis has been eliminated from most countries in the world. most countries in the world.

Poliomyelitis infections have fallen by Poliomyelitis infections have fallen by 99%, and some five million people have 99%, and some five million people have escaped paralysis. escaped paralysis.


Between 2000 and 2007, measles Between 2000 and 2007, measles deaths dropped worldwide by deaths dropped worldwide by over 74%, and some regions have over 74%, and some regions have set a target of eliminating the set a target of eliminating the disease.disease.

Maternal and neonatal tetanus Maternal and neonatal tetanus has been eliminated in 12 of the has been eliminated in 12 of the 58 high-risk countries.58 high-risk countries.


Benefits of immunizationBenefits of immunization

Vaccine Type Route

BCG Live attenuated Bacteria Intradermal

DTPD&T = Toxoids

P = inactivated bacteriaIntramuscular

Hepatitis B(HBV) Inactivated viral antigen Intramuscular

Haemophilus

Influenza b(Hib) Polysaccharide

Intramuscular

MMR Live attenuated viruses Subcutaneous

OPV Live attenuated virusOral

IPV Inactivated virusIntramuscular

BCG = BCG = Bacillus Calmette – Guerin vaccine (tuberculosis).Bacillus Calmette – Guerin vaccine (tuberculosis).DPT = DPT = Diphtheria, pertussis and tetanus vaccine.Diphtheria, pertussis and tetanus vaccine.MMR =MMR =Live attenuated measles, mumps and rubella viruses in a combined vaccine.Live attenuated measles, mumps and rubella viruses in a combined vaccine.IPV =IPV = Inactivated Poliovirus vaccine Inactivated Poliovirus vaccineOPV =OPV = Oral attenuated poliovirus vaccine Oral attenuated poliovirus vaccine

25/12/201025/12/2010 3535Dr. Salwa TayelDr. Salwa Tayel

The EndThe End


Thank YouWebsite http://faculty.ksu.edu.sa/73234/default.aspx

[email protected]

25/12/2010dr. salwa tayel1. 25/12/2010dr. salwa tayel2 associate professor family and community...

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