PREVENTION

1. PREVENTION /CONTROL and ERADICATION ofCommunicable Diseases Dr. Abdalla Abdelwahid Saeed Consultant Community Medicine Tuesday 4.11.1431H

2. PREVENTION/CONTROL AND ERADICATION OF COMMUNICABLE DISEASES OBJECTIVES : 1-REVIEW OF COMMUNICABLE DISEASE EPIDEMIOLOGY 2-DEFINTIONS OF TERMS: PREVENTION, CONTROL, ERADIACTION PRINCIPLES OF PREVENTION, CONTROL AND ERADICATION OF COMMUNICABLE DISEASES ERADICATED DISEASES ( SMALL POX) NON COMMUNICABLE DISEASES PREVENTION/CONTROL

3. DEFINITIONS PREVENTION : PRIMARY PREVENTION OF DISEASE- DISEASE WILL NOT OCCUR CONTROL : DECREASING LEVEL OF DISEASE TO ACCEPTABLE LEVEL OF NO CONCERN TO AUTHORITY AND COMMUNITY ERADICATION: DECREASING LEVL OF DISEASE TO ZERO LEVEL. DISEASE DOES NOT OCCUR AGAIN

4. LEVELS OF PREVENTION 1-PRIMORDIAL � PREVENT RISK FACTORS 2-PRIMARY : REVERSE , REDUCE RISKFACTORS 3-SECONDARY : PROMPT DIAGANOSIS AND TREATMENT 4-TERTIARY: REHEBILITATION

5. Definitions Control: The reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable level as a result of deliberate efforts; continued intervention measures are required to maintain the reduction. Example: diarrhoeal diseases. Elimination of disease: Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts; continued intervention measures are required. Example: neonatal tetanus. Elimination of infections: Reduction to zero of the incidence of infection caused by a specific agent in a defined geographical area as a result of deliberate efforts; continued measures to prevent re-establishment of transmission are required. Example: measles, poliomyelitis.

6. Definitions Eradication: Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed. Example: smallpox. Extinction: The specific infectious agent no longer exists in nature or in the laboratory. Example: none.

7. Magnitude COMMUNICABLE DISEASES ( DISEASES TRANSMITTED FROM PERSON TO PERSON) WERE IMPORTANT PROBLEMS WORLDWIDE. WITH DEVELOPMENT AND IMPROVED QUALITY OF LIFE THEY WERE SIGNIFICANTLY REDUCED IN TERMS OF INCIDENCE AND PREVALENCE IN MOST DEVELOPED ( RICH ) COUNTRIES. THEY ARE STILL MAJOR HEALTH PROBLEMS IN MANY DEVELOPING COUNTRIES. IN THE KINGDOM SOME OF THEM ARE STILL PREVALENT AND HAJJ AND OMRA SEASONS ARE RISK SEASONS FOR IMPORTING SOME INFECTIOUS DISEASES. EVEN IN DEVELOPED DISEASES SOME INFECTIOUS DISEASES STARTED TO REAPPEAR AGAIN ( REEMERGING ) AND SOME NEW DISEASE ARE APPEARING IN THE WORLD ( EMERGING DISEASES) SUCH AS SARS. SO THE STUDY OF INFECTIOUS DISEASES IS STILL IMPORTANT FOR HEALTH STUDENTS IN THE KINGDOM AND IN OTHER COUNTRIES.

8. REVIEW OF EPIDEMIOLOGY OF COMMUNICABLE DISEASES FOR ANY INFECTIOUS DISEASE TO BE PRESENT AND BE TRANSMITTED IN THE COMMUNITY TWO FACTORS ARE ESSENTIAL : 1- SOURCE : THERE MUST BE A SOURCE FOR THE DISEASE. SOURCE IS HUMAN , ANIMAL , ENVIRONMENT ETC� WHERE THE CAUSATIVE AGENT IS FOUND AND BE TRANSMITTED TO OTHERS.

9. CONTD� 2- SUSCEPTIBLE HOST : PERSON AT RISK BECAUSE IS EXPOSED TO DISEASE AND HAS NO IMMUNITY OR PROTECTION AGAINST THE DISEASE.

10. CONTD� IN SOME DISEASES A THIRD FACTOR IS NECESSARY SUCH A VEHICLE OR A VECTOR TO TRANSMIT THE CAUSATIVE AGENT FROM SOURCE TO SUSCEPTIBLE HOST

11. EPIDEMIOLOGY OF COMMUNICABLE DISEASES A HUMAN SOURCE CAN BE : 1.1. PATIENT WITH SYMPTOMS 1.2. CARRIER WITHOUT SYMPTOMS THE CARRIER CAN BE : 1.2.1. INCUBATING CARRIER DURING THE INCUBATION PERIOD WHICH IS THE PERIOD BETWEEN ENTRANCE OF CAUSATIVE AGENT AND APPEARANCE OF SYMPTOM 1.2.2. CONVALASCENT CARRIER DURING THE CONVALASCENCE PERIOD AFTER THE DISAPPEARNCE OF SYMPTOMS CARRIERS CAN BE ACUTE (TEMPORARY) CARRIER FOR SHORT PERIOD OR CHEONIC ( PERMENANT ) FOR LONG PERIOD. 2- SUSCEPTIBLE HOST : PERSON AT RISK BECAUSE IS EXPOSED TO DISEASE AND HAS NO IMMUNITY OR PROTECTION AGAINST THE DISEASE.

12. EPIDEMIOLOGY OF COMMUNICABLE DISEASES IN SOME DISEASES A THIRD FACTOR IS NECESSARY SUCH A VEHICLE OR A VECTOR TO TRANSMIT THE CAUSATIVE AGENT FROM SOURCE TO SUSCEPTIBLE HOST. SO THE TRANSMISSION CAN BE DIRECT FROM SOURCE TO SUSCEPTIBLE OR INDIRECT REQUIRING A VEHICLE OR A VECTOR. A VEHICLE IN NON LIVING SUCH AS AIR, FOOD, WATER, FOMITES ( CLOTHES ETC.. ) , DISHES, FORK, SPOONS, KNIVES ETC�

13. CONTD�.. A VECTOR IS A LIVING AGENT CAPABLE OF THRANSMITTING THE DISEASE SUCH AS MOSQUITOE, FLIES, LICE, FLEAS ETC� . THIS TRANSMISSION CAN BE BIOLOGICAL IF CAUSATIVE AGENT ENTERS INSIDE THE BODY AND CHANGE IN FORM ( DEVELOPMENT) ONLY KNOWN AS CYCLODEVELOPMENTAL ( SUCH AS FILARIASIS � ELEPHANTIASIS ) WHERE MICROFILARIA DEVELOPS AND CHANGE INTO ADULT WORM WITHOUT MULTIPLICATION )- OR KNOWN AS PROPAGATIVE( MULTIPLICATIVE) IF THERE IS ONLY MULTIPLICATION WITHOUT DEVELOPMENT SUCH AS IN PLAGUE

14. CONTD�.. OR CAN BE CYCLOPRORGATIVE IF THERE IS BOTH DEVELOPMENT AND MULTIPLICATION SUCH AS NIN MALARIA WHERE THE GAMETOCYTES INCREASE IN NUMBERS AND CHANGE TO INFECTIVE STAGE OF SPOROZOITES. IN SOME DISEASES THERE IS A NEED FOR AN INTERMEDIATE HOST ( WHERE NON SEXUAL MULTIPLICATION OF THE CAUSATIVE AGENT TAKES PLACE ) SUCH AS SNAILS IN SCHISTOSOMISIS WHERE MIRACIDIA FROM THE EGGS DEVELOP INTO CERCARIA WHICH ARE THE INFECTIVE STAGE TO THE DEFINITIVE HOST WHERE THE SEXUAL MATURATION AND MULTIPLICATION TAKE PLACE.

15. PRINCIPLES OF CONTROL OF COMMUNICABLE DISEASES: TO CONTROL ANY COMMUNICABLE DISEASE YOU HAVE TO BREAK THE INFECTIOUS CIRCLE AT THE SOURCE, SUSCEPTIBLE HOST OR VECTOR OR IN ALL OF THEM AS FOLLOWS :

16. CONTROL CONTD� A- SOURCE : HUMAN : PATIENT : 1-TREAT ( CORRECT DRUG, DOSE , DURATION ) , CONFIRM CURE BY DISAPPEARNCE OF SYMPTOMS AND SIGNS AND LABORATORY TESTS.THE PATIENT HAVE THE DISEASE 2- ISOLATION : THIS IS NECESSARY IF DISEASE IS DIRECTLY TRANSMITTED WITH LOW OR NO CARRIERS AND THE DISEASE IS VERY SERIOUS . IT IS MORE PRACTICAL IF DISEASE IS OF SHORT DURATION. IT IS USUALLY NOT DONE FOR VERY MILD DISEASES.ISOLATION CONTINUES TILL THE PATIENT IS FULLY CURED .

17. CONTROL CONTD ISOLATION CAN ALSO BE FOR CERTAIN SYSTEMS OF THE PATIENT AND NOT FOR THE WHOLE PATIENT � 2.1. RESPIRATORY ISOLATION 2.2. ENTERIC ISOLATION 2.3. SEXUAL ISOLATION 2.4. CONTACT ISOLATION

18. CONTROL CONTD 3- HEALTH EDUCATION : THIS IS IMPORTANT FOR ALL DISEASES. THIS INCLUDE THE MESSAGE , THE METHOD , FOR WHOM AND WHY.HOW TO AVOID INFECTING OTHERS. 4-DISINFECTION: KILLING CAUSATIVE AGENTS COMING OUT OF THE PATIENT . THIS CAN BE CONCURRENT ( CONTINUOUS) OR TERMINAL ( AT END OF DISEASE IF PATIENT IS TREATED OR DIED) CARRIER : LOOK FOR CARRIERS IN CONTACTS OF PATIENTS AND OTHERS BY EXAMINATION AND LAB. INVESTIGATIONS. IF FOUND APPLY THE SAME MEASURES APPLIED TO PATIENTS. IF SOURCE IS ANIMAL ( ZOONOSIS) YOU CAN TREAT OR ERADICATE . THE CARRIER HAS THE INFECTION.

19. CONTROL CONTD 5- QUARANTINE : OF CLOSE CONTACTS OF OPEN CASES OF SOME DISEASES DIRECTLY TRANSMITTED FOR THE MAXIMUM INCUBATION PERIOD. QUARNTINE CAN BE : 5.1. STRICT QUARANTINE AS IN ISOLATION 5.2. MODIFIED QUARANTINE ( PERSON SURVEILLANCE � MONITORING) WHERE THE PERSON IS OBSERVED AT HOME OR WORK AND REQUESRED TO REOPRT IF SYMPTOMS ARISE OR REPORT REGULARLY FOR MEDICAL EXAMINATION.

20. CONTROL CONTD/ DISEASE PREVENTION B- SUCECPTIBLE HOST: 1- RAISE SOCIOECONOMIC CONDITIONS AND IMPROVE QUALITY OF LIFE- ENVIRONMENTAL SANITATION � SAFE , ADEQUATE WATER SUPPLY, PROPOER REFUSE COLLECTION AND DISPOSAL , PERSONAL AND GENERAL HGYIENE AND FOOD AND FOOD HANDLERS HYGIENE, LITERACY, HEALTH SERVICES, HOUSING ETC�.. 2- HEALTH EDUCATION- MESSAGE , METHOD AND WHY . HOW TO AVOID CONTRACTING THE DISEASE .

21. CONTROL CONTD 3- SPECIFIC PROTECTION: 3.1.PHYSICAL ENVIRONMENT, PROTECTIVE CLOTHES, SCREENS, BED NETS 3.2 CHEMICAL : PROTECTION BY DRUGS ( CHEMOPROPHYLAXIS) 3.3 BIOLOGICAL : BY PASSIVE ( IMMUNOBLOBULINS) OR ACTIVE ( VACCINES ) IMMUNIZATION OR ACOMBINATION OF BOTH

22. IMMUNIZATION VACCINES : DERIVED FROM CAUSATIVE AGENTS ACTIVE by giving vaccines derived from causative agent these can be live, live attenuated (weakened), killed (INACTIVATED) or toxoid (weakened toxins)- body will make antibodies GOOD VACCINE is safe, effective, cheap, easy to administer, one dose, acceptable EXPANDED PROGRAM OF IMMUNIZATION ( E.P.I.) OTHER VACCINES ADULT VACCINATION

23. CONTROL CONTD C- VECTOR OR INTERMEDIATE HOST : ERADICATE OR CONTROL VECTOR OR INTERMEDIATE HOST OR DECREASE CLOSE CONTACT OF VECTOR WITH BOTH SOURCE AND SUSCEPTIBEL HOST BY: 1. PHYSICAL METHODS : CHANGE ENVIRONMENT SO THAT IT IS NO LONGER SUITABLE FOR PRESENCE OR MULTIPLICATION OF VECTOR SUCH AS DRYING OR FILLING OF SWAMPS AND CANALS.

24. CONTROL CONTD 2- CHEMICAL : BY CHEMICAL COMPOUNDS SUCH AS INSECTICIDES FOR INSECTS, RODENTICIDES FOR RODENTS AND MOULLSCIDES FOR SNAILS. INSECT REPELLANTS ARE CHEMICAL COMPOUNDS APPLIED TO SKIN SURFACE OF HUMANS TO REPELL INSECTS FROM BITING. 3- BIOLOGICAL : BY CERTAIN ANIMALS WHICH KILL OR EAT VECTOR SUCH AS GAMBUSIA FISH WHICH EATS THE LARVAE OF CERTAIN MOSQUITOES OR CERTAIN PLANTS WHICH CAN KILL THE VECTOR OR THE INTERMEDIARE HOST.

25. Eradication Eradication is the reduction of an infectious disease's prevalence in the global human or animal host population to zero.[1] It is sometimes confused with elimination, which describes either the reduction of an infectious disease's prevalence in a regional population to zero, or the reduction of the global prevalence to a negligible amount

26. Eradication Attempts Seven attempts have been made to date to eradicate infectious diseases in humans globally - four aborted programs targeting hookworm, malaria, yaws, and yellow fever, one successful program targeting smallpox and two ongoing programs targeting poliomyelitis and dracunculiasis. Five more infectious diseases have been identified as of April 2008 as potentially eradicable with current technology by the Carter Center International Task Force for Disease Eradication - measles, mumps, rubella, lymphatic filariasis and pork tapeworm

27. ERADICATION SMALL POX: has been eradicated from the world but we teach it to know how was it eradicated and whether we can use similar or modified strategies to eradicate other infectious diseases Occurrence: previously worldwide-, last natural human case 1977 in Somalia . last lab. case in 1978, in Birminghm , Uk. eradication certified by W.H.O in 1980.

28. Small pox eradication live attenuated vaccine, safe , effective, easy to administer � skin scratching - eradication of smallpox: phases : 1- preparatory phase 2- attack phase ( vaccination ) 3- consolidation phase 4- maintenance phase factors helped in eradication success : serious disease, international, direct transmission, no vectors, no non human source, no carriers, easy recognizable clinical features, excellent vaccine , but international cooperation was very effective.

29. Terms Containment � to contain the disease as to prevent it from becoming a worse problem. Containment is usually the only option available for the majority of infectious diseases. Elimination � to eliminate the disease even though the infectious agent may remain e.g. rabies and polio had been eliminated in many countries, and probably SARS in 2003. Eradication � to eradicate the infectious agent altogether worldwide e.g. smallpox

30. Eradication of Smallpox The initial strategy was separated into 3 phases; Attack phase - This applied to areas where the incidence of smallpox exceeded 5 cases per 100,000 and where vaccination coverage was less than 80%. Attention was given to mass vaccination and improvement in case surveillance and reporting. This phase lasted from 1967-1973. A large amount of financial resoureces were provided for setting up surveillance centres and reference centres. Priority was given to Brazil, sub-saharan African, S.Asia and Africa.

31. Eradication of Smallpox Consolidation Phase - In areas where the incidence was less than 5 cases per 100,000 and vaccination coverage exceeded 80%, the objective was the elimination of smallpox. Vaccination uptake was to be maintained and surveillance improved. Facilities should be made available for isolation. Maintenance Phase - once smallpox had been eliminated, it was essential it was not reintroduced. This phase was entered in 1978. In 1980, the world was declared to be free of smallpox.

32. Features that made Smallpox an eradicable disease 1. A severe disease with morbidity and mortality 2. Considerable savings to developed non-endemic countries 3. Eradication from developed countries demonstrated its feasibility 4. No cultural or social barriers to case tracing and control 5. Long incubation period 6. Infectious only after incubation period 7. Low communicability

33. Contd.. 8. No carrier state 9. Subclinical infections not a source of infection 10. Easily diagnosed 11. No animal reservoir 12. Infection confers long-term immunity 13. one stable serotype 14. Effective vaccine available

34. Contd.. 2 strategies used: 1. vaccination campaigns to immunize 80% of the population. 2. surveillance and containment of cases and outbreaks.

35. EPIDEMIOLOGY OF NON COMMUNICABLE DISEASES DEFINITION : NO AGREED DEFINITION � IMPAIRMENT OF BODY STRUCTURE AND / OR FUNCTION PERSISITING FOR LONG PERIOD NECESSITATING MODIFICATION OF NORMAL LIFE� EUROPE � IMPAIRMENTS, DEVIATIONS FROM NORMAL WHICH ARE : PERMENANT , WITH RESIDUAL DISABILITY, ,NON REVERSIBLE PATHOLOGY, REQUIRES PATIENTS TRAINING / REHABILITATION WITH LONG PERIOD OF SUPERVISION� USA

36. MAGNITUDE OF PROBLEM : INCEASING WORLDWIDE AMONG ADULTS,. CVD AND CANCERS CAUSE 70 - 75 % OF DEATHS IN DEVELOPED COUNTRIES. THE INCREASE IS DUE TO INCREASED LIFE EXPECTANCY- CHANGE IN LIFESTYLE , , MODERN MEDICAL CARE, SHARED RISK FACTORS: SMOKING, ALCOHOL, LIFE-STYLE, ENIRONMENT RISKS, STRESS, FAILURE TO UPTAKE PREVENTIVE SERVICES. GAPS IN NATURAL HISTORY : ABSENCE OF KNOWN AGENT MULTIFACTORIAL LIFE- STYLE IDEFINITE ONSET PREVENTION AND CONTROL STRATEGIES SHOULD TAKE ALL THESE FACTORS IN CONSIDERATION USING A COMPREHENSIVE AND INTEGRATED APPROACH.

37. Problems in chronic non communicable diseases0 lack of specific causative agent Indefinite onset of disease Long latent period Multiple possible etiological factors Identify Causative factor(s) Identify risk factors Risk factors : A- Modifiable B- Non modifiable

38. NON COMMUNICABLE DISEASE ( MOSTLY CHRONIC LEVEL OF PREVENTION PRIMORDIAL PREVENTION : prevent occurrence of risk factors- counseling, health education PRIMARY PREVENTION: prevent occurrence of disease- by reversing or reducing risk factors by health education SECONDARY PREVENTION: prevent spread or complications by screening programs ( early diagnosis and proper and quick treatment) TERTIARY PREVENTION: prevent disability by rehabilitation, physical, social, psychological and occupational

39. THANK YOU BEST WISHES TO ALL