Englishcoursewareofinfluenzalecture目录contents•Introduction•Virologicalcharacteristicsofinfluenza•Epidemiologicalcharacteristicsofinfluenza01IntroductionDefinitionInfluenza,commonlyknownastheflus,isahighlycontagiousdiseasecausedbyinfluenzavirusesTypesofInfluenzaTherearethreetypesofinfluenzaviruses-A,B,andC.InfluenzaAvirusesarefurtherclassifiedintosubtypesbasedonthetwoproteinstheypose,hemagglutinin(H)andneuraminidase(N)DefinitionofInfluenzaHistoricalBackgroundInfluenzahascausedseverepandemicsthroughouthistory,withthemostseverebeingthe1918SpanishflupandemicsthataffectedmillionsofpeopleworldwideCurrentSituationSeasonalinfluenzaepicsoccurrenceannually,resultinginsignificantmorbidityandmoralityTheWorldHealthOrganization(WHO)monitorsthecirculationofinfluenzavirusesandrecommendationsvacuumtopreventthespreadofthediseaseHistoryandCurrentSituationofInfluenza•Purpose:Thepurposeofthiscaptureistoprovideanoverviewofinfluenza,includingitscauses,transmission,clinicalrecommendations,prevention,andcontrolmeasuresPicturePurposeandObjectivesObjectives+Understandthedefinitionandtypesofinfluenzaviruses+LearnaboutthehistoricalbackgroundandcurrentsituationofinfluenzaPicturePurposeandObjectives+Familiarizeyourselfwiththeclinicalrecommendationsandapplicationsofinfluenza+Understandtheimportanceofinfluenzapreventionandcontrolmeasures,includingvacancyandantiviraltreatment+ApprovetheglobaleffectsinmonitoringandrespondingtoinfluenzabreakthroughsPicturePurposeandObjectives02VirologicalcharacteristicsofinfluenzaInfluenzaA:Thistypeofvirusisfoundinbirds,humans,pigs,andotherhorsesItcancauseseveresymptomsandpandemicsduetoitsabilitytomutatequicklyandspreadeasilyfrompersontopersonTherearemanydifferentsubtypesofInfluenzaA,suchasH1N1andH3N2,whichhavecausedsignificantbreakthroughsinthepastInfluenzaB:ThistypeofvirusisprimarilyfoundinhumansandcauseslesssevereIllnessthanInfluenzaA.UnlikeInfluenzaA,thereareonlyafewsubtypesofInfluenzaB,andtheytendtocauselocalizedbreakthroughscomparedtopandemicsInfluenzaC:ThistypeofvirusisrareandgenerallycausesmillrespiratoryillnessItisnotthoughttocauseepicsorpanelsTypesandsubtypesofinfluenzavirusesThestructureandcharacteristicsofinfluenzaviruses•Structure:Influenzavirusesareenvelopedviruseswithanegativesense,singlestrandedRNAgeneThevirusparticleiscomposedofaninnernucleusencapsulatedbyanenvelopederivedfromthehostcellmembraneTheenvelopeiscoveredwithspikesmadeupoftwovirtualproteins,hemagglutinin(HA)andneuraminidase(NA),whichplaykeyrolesinvirusattachment,entry,andreleasefromhostcells•Characteristics:InfluenzavirusesarehighlycontagiousandcanspreadthroughrespiratorydropletsorcontactswithcontiguoussurfacesTheyhaveanincubationperiodofabout1-4days,whichmeansthataffectedindividualsmaynotshowsymptomsuntilseveredaysafterinfectionInfluenzavirusesarealsohighlymutable,whichallowsthemtomodifytheimmunesystemandcontributetotheemergencyofnewtrainsandbreakthroughsTheMutationandEvolutionofInfluenzaViruses•Antigenicdrive:Thisisaroutineprocessofmutationthatoccursinthesurfaceproteinsofthevirus,allowingittoevaluatetheimmunesystemandcontinuetoaffectindividualsAntigenicdriftisresponsiblefortheannualobservationsofinfluenza,asthevirusmutatesenoughtoaffectpeoplewhohavebeenexposedtopreviousstrands•Antigenicshift:Thisisaminorandmajorchangeintheinfluenzavirusthatoccurswhentwodifferentstrandsaffectthesameho...
