DISEASE PREVENTION & CONTROL

1. DISEASE PREVENTION & CONTROL a brief extract from K.Park (19thed)

2. OBJECTIVE To reduce incidence, prevalence & consequences of disease C Community participation, Political support & Intersectoral co-ordination

3. Although effective control requires knowledge of multifactorial causation ESSENTIAL or WEAKEST link – may be sufficient for disease control • Eg., cholera epidemic in London - WATERPUMP

5. At reservoir level 1. Early diagnosis • 1st step in control • USE • Treatment, • epidemiological investigations, • descriptive epidemiology, • institution of control measures

8. 2. Notification • Enables early detection of outbreaks • 1st health info sub-system to be established • Made by physician, head of the family or lay people (anyone) Under IHR • Cholera Plague & yellow fever (1983) • under WHO surveillance - lbTF RF PP VI Malaria etc.,

9. 3. Epidemiological investigationsFOR • Identification of source of infection • Factors influencing its spread in community • Character of agent, reservoir, vectors, vehicles and susceptible host populations, geographical, climatic, social, cultural, behavioral pattterns

10. 4. Isolation • separation, for a period of communicability of infected animals or persons from others in such places & under such conditions, as to prevent or limit direct or indirect transmission of infectious agent from those infected to those who are susceptible, or who may spread the agent to others

11. OBJECTIVE- to prevent transfer of infection • Types • standard • Strict • Protective • High security • Oldest CD control measure

12. Isolation by ring immunization • Encircling infected persons with a barrier of immune persons • Eradication small pox worldwide(60&70s) • Measles N.America INEFFECTIVE • large component of subclinical infection Eg. Polio Hepatitis A TyphoidFever • Highly infectious disease before diagnosis Eg. mumps

13. Replaced by surveillance • Pertusis-4 wks • TB-3 wks after chemotherapy • Hepatitis A-3 wks • Polio-2 wk adult 6 wk ped. • Mumps-till swelling subsides • Shigellosis, salmonellosis-3 conseq. –ve stool cult. • Chickenpox 6days after rash appears • HZ-6 days after rash appears • Influenza-3 days after onset • Measles 3rd day of rash • Cholera, diphtheria-until 48hrs of antibiotics • Meningitis(meningo&streptococcal)-until 6hs of antibiotics

14. SWINE FLU • All schools, gyms and courts have been closed, and restaurants in Mexico City have been ordered to serve only take-out food until 6 May to prevent contagion. Surgical masks have been given to the public in the capital

15. 5. Treatment • AIM – to kill infectious agent when it is still in reservoir i.e., before dissimination • RESULT – reduced communicability of disease, less duration of disease, prevents development of secondary cases • NO disease has ever been prevented through treatment Eg. yaws

16. 6. Quarantine “ limitation of freedom of movement of such well persons or domestic animals exposed to CD for a period of time not longer than the longest usual incubation period of disease in such manner as to prevent effective contact with those not so exposed” • Absolute, Modified or segregation • Replaced by active surveillance

17. Interruption of transmission • May be by changing man’s environment Eg. Water treatment for water borne diseases, Clean practices for food borne diseases, Vector control

18. The susceptible host 1. Active Immunization • most powerful & cost effective method. • Strengthens host defenses • control of some ID solely based on active immunization e.g., polio, tetanus, diphtheria& measles • Routine-during infancy & early childhood e.g., NIS • special-high-risk groups or • specific geographic area • e.g., cholera, plague, typhoid, influenza, yellow fever

19. No vaccine for every ID & not 100% effective • Immunization augments herd immunity- disease difficulty to spread. • Infinite number of immunization schedules. • Good schedule=> • Epidemiologically relevant, • Immunologically effective, • Operationally feasible, • Socially acceptable.

21. 2. Passive immunization • short term immunity • limited value in mass control • Preparations • Normal human Ig • Specific human Ig • IG—HepA, HepB, Hep non-A non-B, Rubella, Varicella-zoster, Measles, Rabies, Tetanus, Rh isoimmunization • Anti sera or anti toxins • Diphtheria Tetanus Gas gangrene Rabies Botulism

22. 3.Combined passive and active immunization • e.g., tetanus diphtheria rabies • Ig should not be given within 3weeks before or until 2wks after administration of live attenuated vaccines • exception hepB vaccine and ig

23. 4. Chemoprophylaxis • Causal – complete prevention of infection by early elimination of invading or causal agent • Clinical – prevention of clinical symptoms • Indications Cholera, conjunctivitis, diphtheria, influenza, malaria, meningitis, plague(pneumonic)

24. 5. Non-specific measures • Improvement in quality of life • Legislative measures • Community involvement • Played a major role in decline of TB, Cholera, Leprosy and child mortality in industrialized nations

26. obstacles • Scarcity of funds • Lack of effective health infrastructure, trained personnel, supplies, labs, equipment • Public awareness needed for investigation & control • Human behaviour (health education) • Integration of CD control with PHCare

27. SWINE FLU • masks are not bio-chemical suits. Masks are obviously just covering one part of the body so your hands and clothes could all have the virus on and when you take them off you will infect yourself. (Dr Ronald Cutler, deputy director of biomedical science at the University of London) • Masks alone will not prevent spread of the influenza virus and basic hygiene measures like hand washing, safe use and disposal of tissues and cleaning of environmental surfaces are key to preventing infection transmission (Gail Lusardi, an infection control specialist at Glamorgan University)

28. SURVEILLANCE • Continuous scrutiny of all aspects of occurrence and spread of disease that are pertinent to effective control • Follows control measures • Objective : Prevention

29. Imp. Diseases (malaria, flu ,polio etc) • Timely warnings • international

30. It includes • Passive reporting of cases • Lab confirmation of presumptive diagnosis • Finding source of infection & routes of transmission • Identification of all cases, susceptible contacts & people at risk • Serological surveillance (identify patterns of present & past infection)

31. Evaluation of effectiveness of control measures • Identify reasons for failures if not successful • Then modify existing measures & continue evaluation

32. SWINE FLU • India • Preventative measures such as surveillance at ports and nine international airports have been taken, and people have been advised to defer non-essential travel to the affected areas. About 50,000 passengers who have come from countries affected by swine flu have been traced and checks would be carried out on them

33. THANK YOU prof assoc. & asst. profs PGs friends for attending

34. Public health – prevent promote protect