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EPIDEMIOLOGICAL TRIAD VED.pptx
- 2. I N TRO D U CT I O N Forlongtimemanwasgroupingindarknessaboutthe causationofdiseases, Severaltheoryofdiseaseswereadvancedfromtimeto tim etoExplaindiseasecausationsuchas:- Supernatural theory Theoryofhum ors byGreekandI ndians Theoryofcontagion Them iasm atic theory Theoryofspontaneousgenerationetc K. Park’s textbook of preventive and social medicine 25th edition
- 3. G ermTheoryofD isease The breakthrough came in 1860,when French bacteriologist Louis Pasteur dem onstrated the presence of bacteria in air. I n 1 87 3 he advancedtheoryofSpontaneousgeneration.. Later Robert Koch discovered anthrax caused by bacteria and G OLDEN ERA of Bacteriology begun w ith discovery of m icrobe aftermicrobe.. G onnococus in1 879 Typhoidbacillus,Pneumococciin1 8 8 0 T uberclebacillusin1 882 Cholerain1 883 D iptheriain1 884andsoon … Louis Pasteur K. Park’s textbook of preventive and social medicine 25th edition
- 4. All attentionw as focusedonm icrobes andtheir rolein diseasecausation,anddiseasemodelaccordinglyis:- • D I SEASEAGENT MAN D I SEASE • • I n1 878RobertKochsum m arizedhis experim ents ontheetiologyofw ound infection,Byinoculatinganim alsw ith m aterial fromvarioussources,he producedsixtypesofinfection,each causedbyaspecific m icroorganism . • H ethentransferredtheseinfections by • inoculationthroughseveral kindsof animals,reproducingtheoriginalsix types. Robert Koch K. Park’s textbook of preventive and social medicine 25th edition
- 5. Inthatstudy,heobserveddifferencesin pathogenicityfor differentspeciesofhostsanddemonstratedthatthe animalbodyisanexcellentapparatusforthecultivationof bacteria. K. Park’s textbook of preventive and social medicine 25th edition Thesetheories ofPasteur andKochconfirm edthegerm theoriesofdisease. Later,RobertKochhasgivenKochPostulates
- 6. Aspecificmicroorganismisalwaysassociatedwith agivendisease. Themicroorganismcanbeisolatedfromthediseased anim al andgrow ninpurecultureinthelaboratory. Theculturedmicrobewillcausediseasewhen transferredtoahealthyanim al. Thesametypeofmicroorganismcanbeisolatedfrom thenew lyinfectedanim al. K. Park’s textbook of preventive and social medicine 25th edition Koch’spostulates,are:
- 7. TheGermtheoryhasmanylimitation,Itwas unabletoexplain Whyonlysomepeoplesuffer fromthediseaseafter exposure to microorganism and not all,as with exposuretotuberclebacilli. Whysomepeopledonotsufferfromthedisease eventhroughtheyharborthepathogeninthebody.As incarrier state This lead to demand of a broader concept of disease causation that synthesized the basic factorsofAgent,HostandEnvironment. K. Park’s textbook of preventive and social medicine 25th edition
- 8. Thelimitationofgermtheoryledtotheconceptof “Epidem iological orEcological T riad”. AccordingtothetheoryofEpidem iological triad everyone exposedtodiseaseagentdidnotcontractthedisease, Thismeansitisnotonlythecausativeagentthatis responsiblefor disease. ButthereareanotherFactorsalsorelatedtoManand Environmentwhichcontributestodisease. K. Park’s textbook of preventive and social medicine 25th edition
- 9. AGENT K. Park’s textbook of preventive and social medicine 25th edition HOST ENVIORNMENT
- 10. AGENT K. Park’s textbook of preventive and social medicine 25th edition BIOLOGICAL MECHANICHAL NUTRITIONAL PHYSICAL/CHEMICAL
- 11. HOST K. Park’s textbook of preventive and social medicine 25th edition GENETIC MAKEUP AGE/SEX LITERACY INCOME LIFE STYLE IMMUNITY
- 12. ENVIRONMENT K. Park’s textbook of preventive and social medicine 25th edition PHYSICAL BIOLOGICAL PSYCHOLOGICAL CUSTOMS
- 13. AccordingtothismodelofEpidemiologicaltriad diseaseoccurswhentheequilibriumbetweenagent, hostandenvironm entisdisturbed. K. Park’s textbook of preventive and social medicine 25th edition Thismodelexplainsthatsomepersonsdonotsuffer fromthediseaseeventhroughtheyharbor the pathogens becauseanequilibriumis established betw eenthecausativeagentandthehost.
- 14. Epidem iological triadtheoryis notapplicablefor non infectious andchronicdiseases likeCoronaryartery diseaes,M ental illness etc,becausethese diseasehas m anycauses andm ultiplefactors. Thisledustothinkfor theM ultipleFactorsbehind adiseasecausation. K. Park’s textbook of preventive and social medicine 25th edition
- 15. MULT IFACT ORIALCAUSAT ION K. Park’s textbook of preventive and social medicine 25th edition
- 16. ThetheoryofMultifactorialCausationofDiseasewas firstproposedbyG alenin1 30-1 50AD In1 8 1 9 - 1 9 0 1,thistheorywasagainputforwardby PetenKofer ofG erm any,butthis w as overshadow edby germtheoryatthattim e. G alensaidthefactors are:- Predisposing Exciting and Environmental K. Park’s textbook of preventive and social medicine 25th edition MultifactorialCausationofDisease
- 17. T H ESEPREDI SPOSI N GFACT O RSARE:- SOCIAL ECONOMICAL CULTURAL PSY CH OLOGI CALFACT O R S (I ncludingpoverty,illiteracy,I gnorance, poor livingcondtionO vercrow dingetc) K. Park’s textbook of preventive and social medicine 25th edition
- 18. TUBERCU LOSI S I SN O TM ERELYD U ET OT U BERCLE BACILLI… Factors suchas - • Poverty, • O vercrow dingand • Malnutrition Contributetooccurrenceoftuberculosis K. Park’s textbook of preventive and social medicine 25th edition
- 19. Now it is recognized that a disease is not only causedbyanorganismbutalsopredisposedby m any factors contributingtoits occurrence. For exam ple:- “M odernD iseases”ofcivilization like– lungcancer,diabetes,coronaryheartdiseaseandm ental illnessetchasseveralcontributingfactorsbehindfor thereoccurrence. K. Park’s textbook of preventive and social medicine 25th edition
- 20. I tis nowknow nthatdiseases suchas Coronaryheart diseaseandcancerareduetomultiplefactors. For Exam ple- Excess of fat (saturated) intake, Smoking ,lack of physical exercise and obesity are involved in the Pathogenesis ofCoronaryH eartD isease MostofthesefactorsarelinkedtoLifestyleandhuman behavior. K. Park’s textbook of preventive and social medicine 25th edition
- 21. Groupor Popullations andtheir Charcteristics Enviornment,Behaviour, Culture, Physiological Factors, Ecological Elem ents CausativeFactors T I M E K. Park’s textbook of preventive and social medicine 25th edition
- 22. This m odel of disease causationw as suggestedby MacmahonandPughintheirbook:Epidemiology :Principles andM ethods Thismodelis ideallysuitedinthestudyofchronic disease,wherethediseaseagentisoftennotknown,but istheoutcomeofinteractionofmultiplefactors… K. Park’s textbook of preventive and social medicine 25th edition W EBOFCAU SAT I O N
- 23. The “w eb K. Park’s textbook of preventive and social medicine 25th edition of causation” considered all the predisposing factors of any type and their com plexinter relationshipw itheachother Thefigureillustratesthecomplexitiesofa casualweb ofm yocardial infarctionw hichis bynom eans complete)
- 24. K. Park’s textbook of preventive and social medicine 25th edition
- 25. Thebasic tenetofepidem iologyis tostudythe clusters ofcauseandcom binations of effects andhowtheyrelatetoeachother casual w eb providesamodelwhichshowsvarietyof possibleinterventionsthatcouldbetakento reducetheoccurrenceof disease. TheMultifactorialtheoryhelpsustounderstand thevarious associatedcausativefactors,prioritize andplanmeasuresto controlthedisease K. Park’s textbook of preventive and social medicine 25th edition CONCLUSION
- 26. TH ANKY O U