Avian-influenza.ppt

HumanAvianInfluenza By Dr XinhongLi BirdFlu AvianFluandPeople AsofOctober12 2007 331peoplein12countrieshavebeeninfectedwithH5N1 avianinfluenza and202havediedofthedisease Mostwereinfectedbyclosecontactwithinfectedbirds History 1878 FirstidentifiedcaseinItaly1924 25 FirstU S casesLowpathogenicavianinfluenzafirstidentifiedmid 20thcentury1970 s MigratorywaterfowlcarriersOutbreaksinmink sealsandwhales EconomicImpact Directlosses DepopulationanddisposalHighmorbidityandmortalityQuarantineandsurveillanceIndemnities1978 2003 SeasonaloutbreaksofLPAIinMinnesotacostgrowers 22million EconomicImpact 1983 U S outbreak H5N2 65millioninlossesDestructionof17millionbirds30 increaseineggprices1999 2000 Italyoutbreak H7N1 100millionincompensationtofarmers18millionbirdsdestroyedIndirectlossesof 500million EconomicImpact 1997 HongKongoutbreak H5N1 13millionfordepopulationandindemnities1 4millionbirds2001 HongKongoutbreak H5N1 1 2millionbirds 3 8million EconomicImpact 2003 Europeanoutbreak H7N7 Over33millionbirdsdestroyed ofNetherlands poultrystockCost 2003 2004 SEAsia H5N1 8countries 100millionbirdsdestroyedCost 2004 2005 SEAsiaandEurasiaSpreadtoEurasiabymigratorybirds Definition AnacuterespiratorytractinfectiousdiseasecausedbysomestrainofavianinfluenzaAvirussubtype Keysignsandsymptoms FeverFlowingtearsNasalobstructionCoughPharyngalgiaHeadacheMuscularsorenessGeneralmalaise Etiology ClassificationMorphologicalcharactersAntigenicstructureBiochemicalactivities AvianInfluenzavirus Etiology BelongstothefamilyOrthomyxoviridaeinfluenzaAvirusgenus Classification AvianInfluenzavirus InfluenzaAvirussubtype namedaccordingtothespecies host thestrainisendemicinoradaptedtoBirdfluHumanFluSwineFluHorseFluDogFlu Pathogenicitybasedongeneticfeaturesand orseverityofdiseaseinpoultryLowpathogenicAI LPAI H1toH15subtypesHighlypathogenicAI HPAI SomeH5orH7subtypesLPAIH5orH7subtypescanmutateintoHPAI Etiology 80 120nmindiameterGenomeismerotomy single negativestrandRNA Morphologicalcharacters AvianInfluenzavirus Etiology Antigenicstructure HAisdividedinto16subtypes H1 16 NAisdividedinto9subtypes N1 9 InfectionofinfluenzavirusinhumanisassociatedwithsubtypeH5N1 H9N2 H7N7 H7N2andH7N3caninfecthumanbut and birdspeciesHumaninfluenzaA H5N1 infectionisthemostsevereandhashighcasefatalityrate AvianInfluenzavirus NPprotein Etiology Antigenicstructure AvianInfluenzavirus Antigendrift HAandNAaccumulatemutations RNAvirusimmuneresponsenolongerprotectsfullysporadicoutbreaks limitedepidemics Antigenshift new HAorNAproteinspre existingantibodiesdonotprotectmaygetpandemics Humanvirus Reassortantvirus Non humanvirus MechanismsofInfluenzaVirusAntigenic Shift Etiology Biochemicalactivities Sensitivetoaether chloroform acetoneandsomeotherorganicsolventCanberapidlyinactivatedbycommonlyuseddisinfectant suchasoxidant dilutedacidandhalogencompoundSensitivetohot deactivatedbyheatingupto65 for30minutesor100 over2minutesHasstrongresistivitytolowtemperatureandtheacidenvironmentunderthepH4 0condition AvianInfluenzavirus Epidemiology SourceofInfectionRouteofTransmissionSusceptiblePopulationEpidemiologicFeature Epidemiology SourceofInfection Mainlytheavianspecieswithavianinfluenzaortakingalongwithavianinfluenzavirus suchaschicken duck gooseandsoforthThewildfowlplayanimportantroleinnaturaldisseminationofavianinfluenzaNocaseofhuman to humantransmissionbysmall particleaerosolshasbeenidentified Epidemiology RouteofTransmission Transmittedbytheinhalationofinfectiousdropletsanddropletnuclei bydirect indirectcontactingpoultrysecretionandtheextreta goodsandwatercontaminatedbythevirus withself inoculationontotheupperrespiratorytractorconjunctivamucosaForhumanH5N1 possiblybird to human environment to human AnimalTransmission InitialsourceofinfectionOtherpoultry migratorywaterfowl petbirdsSpreadbyaerosol shareddrinkingwater fomitesVirusinrespiratorysecretionsandfecesViruspresentineggsbuteggsunlikelytosurviveandhatch HumanTransmission Previouslyconsiderednon pathogenicforhumans1997 HongKong18humansinfected 6diedH5N1viruslinkedtooutbreakinlivebirdmarketandareafarms2003 theNetherlands83confirmedcasesinhumans 1death H7N7strain2004 2005 SEAsia118cases 61deaths Indonesia VietNam Thailand CambodiaH5N1strainWithinthevicinityofpoultryoutbreaksEvidenceforhuman to humantransmissionRoleofswineProposed mixingvessel Ifanavianvirusandhuman adaptedvirus swapgenes inaco infectedcellofananimalorhuman a thirdvirus wouldresultthatcouldbereadilytransmittedbyandbetweenhumans Howcouldavianflubecomeeasilytransmissiblefrompersontoperson Epidemiology SusceptiblePopulation Generally humanityisnotsusceptibletoavianinfluenzavirusAnyagemaybeinfectedwithH5N1 theincidenceishigherandtheconditionismoreseriousinthechildrenunder13yrsHigh Riskgroup ThepeoplewhoareengagedinpoultrybreedThepeoplewhohavebeentotheplacesofpoultryraising sellingandslaughteringwithinaweekbeforetheonsetofillnessThelabstaffwhocontacttheavianinfluenzavirusThepersonnelwhohastheclosecontactwithavianinfluenzapatients Epidemiology EpidemiologicFeature WorldwidedistributionReservoirFreeflyingaquaticbirds Ducks geese shorebirds gulls terns auksRecentoutbreaksTheNetherlands Australia Mexico U S SEAsia EurasiaSimilaritytoNewcastleDiseasemakesactualdistributiondifficulttodefineAlteredavianecosystemshavecreatednewnicheforAIviruses ManywildbirdspeciescarrytheseviruseswithnoapparentsignsofharmOtherbirdspecies includingdomesticpoultry developdiseasewheninfectedwithavianinfluenzaviruses PathogenesisandPathology ClinicalManifestations Theincubationperiodisgenerally1 7days usually2 4days DifferentsubtypesofavianinfluenzavirusinfectioncancausedifferentclinicalsymptomsinhumanH9N2 onlyhastheslightupperrespiratorytractinfectionsymptom andpartialpatientsevendonothaveanysymptomH7N7 mainlyperformstheconjunctivitisH5N1 anabruptonset feverandflowingtears nasalobstruction cough pharyngalgia headache muscularsorenessandgeneralmalaiseSeverecases persistenceardentfever theprogressionofdiseaseisrapid haveclinicallyapparentpneumonia ClinicalSignsinHumans 1997 HongKong H5N1 Fever respiratory vomiting diarrhea painFatalcases severebilateralpneumonia liverdysfunction renalfailure septicshock1979 MPAIinharborseals H7N7 Conjunctivitisinhumansincontact2003 Netherlands H7N7 ConjunctivitisMildinfluenzaorrespiratorysymptomsFatalcase acuterespiratorydistresssyndrome2004 2005 S E Asia EurAsia LaboratoryExaminations PeripheralhemogramTheviralantigenandthegenedetectionViralisolationSerologicexaminationImaginginvestigation LaboratoryExaminations Peripheralhemogram Theviralantigenandthegenedetection Theamountoftotalwhitebloodcell TWBC isgenerallynothighorreducedTheTWBCandlymphocytearedecreasedaccompaniedbythereductionofplateletinseverecase TakethepatientrespiratorytractspecimentodetectinfluenzaAvirusnucleoprotein NP matrixprotein M1 oravianinfluenzavirusHsubtypeantigenbyELISAorimmunofluorescenceAvianinfluenzavirussubtypespecificityHantigenicgeneisdetectedbyRT PCR LaboratoryExaminations Viralisolation Serologicexamination Separatevirusfromthepatientrespiratorytractspecimen forexample nasopharyngealsecretion oralcavitygargarism tracheaaspirationorrespiratorytractepithelialcell Theserumantibodiesinpairedserumspecimens consistingofanacuteandaconvalescentserumspecimenaredetectedFourfoldorgreaterrisesintiterareconsidereddiagnosticofinfection LaboratoryExaminations Imaginginvestigation Radiographicchangesincludediffuse multifocalorpatchyinfiltrates segmentalorlobularconsolidationwithairbronchogramsProgressiontorespiratoryfailuremayshowdiffuse bilateral ground glassinfiltrateslungconsolidationimageandmaymergedwithpleuraleffusion Diagnosis EpidemiologycontacthistoryClinicalexaminationLaboratoryinvestigations Diagnosis EpidemiologycontacthistoryHavebeentotheepidemicfocuswithinaweekbeforetheonsetofillnessHavethecontacthistorywiththeaviandiesofillnessHaveintimatecontactwiththeinfectedavianoritssecretionandexcretionHaveclosecontactwiththeavianinfluenzapatientEngagedinthelabresearchrelatedtotheavianinfluenzavirus Diagnosiscriteria MedicalobservationcaseHavetheepidemiologycontacthistoryandappeartheinfluenzaclinicalsituationwithin1weekBorderlinecaseHavetheepidemiologycontacthistoryandclinicalmanifestation respiratorytractsecretionorrelevantorganizationspecimenshowthemasculineofinfluenzaAvirusM1orNPantigenoritscodingnucleiacidexaminationismasculine Diagnosiscriteria ClinicaldiagnosiscaseBorderlinecasehadthesamecontacthistorywiththefinaldiagnosiscaseFinaldiagnosiscaseHavetheepidemiologycontacthistoryandtheclinicalmanifestationandthespecificviruscanbeseparatedfromthepatient srespiratorytractsecretionspecimenortherelevantorganizationspecimen oravianinfluenzavirussubtypespecialantigenornucleicacidinspectionismasculinebyusingothermethod or4timeselevationofpairedserumsubtypestrainantibodytiterintheinitialperiodandrecoveryphase DifferentialDiagnosis InfluenzaCommoncoldBacterialpneumoniaSevereacuterespiratorysyndrome SARS InfectiousmononucleosisCytomegalovirusinfectionChlamadiapneumoniaMycoplasmalpneumoniaLegionaries diseasePneumoniaepidemichemorrhagicfever Treatment Isolation Carryontheisolationtreatmenttotheborderlinecase clinicaldiagnosiscaseandfinaldiagnosiscase Symptomatictreatment Useantipyretia anesisthenasalmucoushyperemiamedicineStopcoughexpectorantsAvoidtousingtheaspirinorthemedicinecontainingtheaspirinaswellasothersalicylicacidpreparationsinchildrenlestofchildren sReye ssyndrome Treatment Antiviraltreatment usedwithin48hrsaftertheinvasion Neuramidinaseinhibitor OseltamivirIonchannelM2retarder AmantadinaandRimantadineZanamivirPeramivirLong actingtopicalneuraminidaseinhibitorsRibavirinInterferon alpha Treatment Strengthenssupportivetreatmentandpreventcomplication Payattentiontorest drinkmorewater increasenutrition givedieteasytodigestGivecloseobservation monitorandpreventcomplication Severecasepatienttreatment SenttotheICUhospitalwardfortreatandcureCarryonoxygentherapypositivelytohypoxemiapatient guaranteebloodoxygenpartialpressure 60mmHg otherwiseconductthemechanicalventilationStrengthentherespiratorytractmanagement preventthemechanicalventilationrelatedcomplication Prophylaxis ControlofthesourceofinfectionStrengthenthemonitorfortheclose contactavianpersonnelStrictlystandardizethehospitalonsetofinfectioncontrolmeasuretothemedicaltherapyunitforpatientsCarryonisolationtreatmenttotheborderlinecase clinicaldiagnosiscaseandfinaldiagnosiscaseCutofftherouteoftransmissionPayattentiontothedietaryhygiene donotdrinkrawwateroreattheundonemeats eggsWashhandsfrequently formthegoodpersonalhygienichabitProtectionofsusceptiblepopulationNoinfluenzaA H5 vaccinesarecurrentlyavailableforhumans Preventionmeasures ImportrestrictionsSurveillanceAppropriatebiosecurityControlhumantrafficIntroductionofnewbirdsintoflockAvoidopenrangerearinginwaterfowlprevalentareasEducationofthepoultryindustryPromptresponsetoMPAIoutbreaks 8StepstoProtectYourselfIndividualpreparednessBeforethepandemiccomesWhenthepandemiccomes