Infectious Disease Epidemiology, Module I Introduction.

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    03-Jan-2016

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<ul><li><p>Infectious Disease Epidemiology, Module IIntroduction</p><p>ANN JOLLY</p></li><li><p>IntroductionRound tableYour expectations of this dayYour career goalsKnowledge baseWhy is infectious disease epidemiology important?</p><p>ANN JOLLY</p></li><li><p>General goalsUnderstand the infectious disease processIdentify transmission routes, modes, media and reservoirsUnderstand public health law Understand infectious disease surveillanceUnderstand the process of outbreak investigation </p><p>ANN JOLLY</p></li><li><p>What causes disease?AgentHostEnvironmentBacteriaVirusesFungiParasitesPrions</p><p>HousingFoodWater qualityAir qualityAgeGenderEthnic groupLifestyleSocioeconomic</p><p>ANN JOLLY</p></li><li><p>ExposureInfectionDisease, symptomatic/asymptomatic</p><p>CarrierConvalescentSequelaeInfectious disease process</p><p>ANN JOLLY</p></li><li><p>What determines infection? </p><p>(other than exposure)The deposition, colonisation and multiplication of an organism in a host,Usually accompanied by an immune responseMay occur with or without clinical illness</p><p>ANN JOLLY</p></li><li><p>Predictors of infection</p><p>AGENTHOSTENVIRONMENTImmunityRaceAgeGenderSocioeconomicLiving ConditionsSocialClimateDoseGeneticsHardinessCommunicability</p><p>ANN JOLLY</p></li><li><p>Infectious disease process - Source ReservoirshumaninsectanimalMediumair bornewater bornefood borne blood bornegenital</p><p>ANN JOLLY</p></li><li><p>Infectious disease process- Transmission RoutedirectOral, oral/faecalsexualrespiratory - droplets or droplet nuclei 1-5mparenteralcongenitalindirectvectorvehicle</p><p>ANN JOLLY</p></li><li><p>Infectious disease process -Infection &amp; IncubationInfectiondoseinfectivityhardinessrate of replicationIncubationinfectiousnessimmune responseintervention</p><p>ANN JOLLY</p></li><li><p>Infectious disease process- DiseaseDiseasesigns, symptomsasymptomatic infectiousOutcome/Prognosismorbiditymortalitysequelaerecoveryinfectious (chronic carrier)</p><p>ANN JOLLY</p></li><li><p>DiagnosisClinicalbased on signs, symptomsLaboratory confirmedmicrobiologydetectionisolationserologyparasitologyvirus</p><p>ANN JOLLY</p></li><li><p>Diagnostic processPatient presentsdue to symptomscase - findingscreeningactive investigation of contacts</p><p>ANN JOLLY</p></li><li><p>Laboratory diagnosisLab tests orderedMethod of collection, site, volumeRight tests orderedcorrect organismsantimicrobial sensitivitySent to the right placeIn the right mediaTransport conditionsTimeTemperature</p><p>ANN JOLLY</p></li><li><p>Laboratory diagnosis, (cont.)Routine identification of organisms causing diarrhoeaC &amp; S shigellaesalmonellaeyersiniaaeromonas campylobacterIn children &lt; 5 in the summerVertoxigenic E. coli</p><p>ANN JOLLY</p></li><li><p>Laboratory diagnosis, (cont.)If food-borne is suspected and written on the requisitionstaph aureusbacillus cereusclostridium perfringens</p><p>ANN JOLLY</p></li><li><p>Interpretation of tests, if positiveTest sensitivity% of people accurately diagnosed as ill of all people testedNormal flora?N. meningitidisStreptococcus pyogenesCarrier stateContamination during collectionLab. ErrorMultiple infections</p><p>ANN JOLLY</p></li><li><p>Interpretation of tests, if negativePrior antibiotic therapyProblems incollectiontimingsitestoragetransportmediaFailure to incubate long enough</p><p>ANN JOLLY</p></li><li><p>Summary</p><p>Infectious disease processreservoir - transmission - disease/deathDeterminants of infectionagent, host, environment interaction</p><p>ANN JOLLY</p></li><li><p>Next Steps Future applieddisease in populationssurveillanceoutbreaks</p><p>ANN JOLLY</p><p>Emphasize multicausation Tuberculosis good e.g..If you are well off and live in good housing, unlikely to be exposed, to get itIf you do, likely to be able to get well. If poor and exposed unlikely to overcome it, become infectious and expose more family and friends. So you have to have the agent, low immunity and poor living conditions etc. for the bug to flourish</p><p>Bicycle accident in childAgent = speed, child not wearing a helmetEnvironment , riding on a busy street</p></li></ul>

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