医学英语-感染病.ppt

IntroductiontoinfectiousdiseasesGangXINDepartmentofMicrobiologyandI18923912518termsInfectiology Infection Infectious diseasesInfectiologist Infectious diseasesarecausedbypathogenicmicroorganisms,suchasbacteria,viruses,parasitesorfungi;thediseasecanbespreaddirectlyorindirectly,formonepersontoanother.Infectious diseasesCommunicablediseasesWound infectionlung infectionpathogenhostOutlinePathogenHostPathogenesisofinfectionClassificationofinfectionClinicalmanifestationsLaboratorydiagnosisofinfectiousdiseasesTreatmentandpreventionpathogenTypesofpathogenseu-,Good;well;truepro-,beforekaruo-,nutorcellnucleusTypesofpathogensSubcelluarProkaryotic Viruses,prionBacterial,chlamydiae,rickettsiae,mycoplasmasEukaryotic Protozoa,fungi,helminthes,arthropodsprionAprionisaninfectiousagentcomposedofproteininamisfoldedformDisease:BovinespongiformencephalopathyMadcow disease(MCD)VirusesThetermvirion(pluralvirions)isalsousedtorefertoasingle,stableinfectiveviralparticlethatisreleasedfromthecellandisfullycapableofinfectingothercellsofthesametypeAvirusisasmallinfectiousagentthatcanreplicateonlyinsidethelivingcellsoforganisms.Bacteria(singular:bacterium)chlamydiaechlamyd-,mantle(acloak)Chlamydia infectionchlamydiaconjunctivitisortrachomarickettsiaeThegenusRickettsiaisnamedafterH.T.Ricketts(18711910),whostudiedRockyMountainspottedfever,andeventuallydiedoftyphusafterstudyingthatdisease.rickets,vitaminDdeficiencyDisease:spottedfever,typhusandscrubtyphusTickhemolymphcellsinfectedwithR.rickettsii.FromtheCDC.SymptomsofScrubtyphusfeverheadachemusclepaincoughgastrointestinalsymptomshemorrhagingandintravascularcoagulation.maculopapularrash,eschar（焦痂）,splenomegalyandlymphadenopathiesaretypicalsigns.http:/ skinTinea pedisTinea manusTinea crurisGroupofextremelysmallsinglecell(unicellular)oracellularorganismsthatarefoundinmoistsoilorwater.Theytendtoexistasparasites,livingoffotherlifeforms.Protos(First)andzoon(animal)protozoa(singular:protozoon)helminthsareworm-likeorganisms(Parasitic worms)thatliveandfeedofflivinghosts,receivingnourishmentandprotectionwhiledisruptingtheirhostsnutrientabsorption,causingweaknessanddisease.helminthsHelmins=wormHookworms attached to the intestinal mucosa.arthropodsGreekarthron,joint,andpodsfoot,whichtogethermeanjointedfeet”Culex MosquitoAedes MosquitoTicksPathogen factorspathogenicityvirulenceistheabilityofapathogentoproduceaninfectiousdiseaseinanorganism.The virulence factors of bacteriaMethodsbywhichbacteriacausediseaseAdhesionColonizationInvasionImmune response inhibitorsToxins12345The virulence factors of bacteriaAdhesion.Manybacteriamustfirstbindtohostcellsurfaces.Colonization.Somevirulentbacteriaproducespecialproteinsthatallowthemtocolonizepartsofthehostbody.Invasion.Somevirulentbacteriaproduceproteinsthateitherdisrupthostcellmembranesorstimulateendocytosisintohostcells.Thesevirulencefactorsallowthebacteriatoenterhostcellsandfacilitateentryintothebodyacrossepithelialtissuelayersatthebodysurface.Immune response inhibitors.Manybacteriaproducevirulencefactorsthatinhibitthehostsimmunesystemdefenses.Toxins.Manyvirulencefactorsareproteinsmadebybacteriathatpoisonhostcellsandcausetissuedamage.Methodsbywhichbacteriacausediseaseinvasionminimum lethal dose(MLD)thesmallestamountoftoxinthatwillkillanexperimentalanimal.Minimuminfectivedosemedian infective dose(ID50)theamountofpathogenicmicroorganismsthatwillcauseinfectionin50percentofthetestsubjects.infective dosethatamountofpathogenicorganismsthatwillcauseinfectioninsusceptiblesubjects.HostfactorssusceptibilitydispositionImmune systemAntibody,immunoglobulinIceberg conceptofinfectionInfectiousdiseasespectrumIfalargenumberofindividualsareequallyexposedtoaninfectiousagent,theydonotallrespondinthesamemanner.Infact,theremaybeabroadrangeofresponses:SomedonotbecomeinfectedatallSomebecomeinfectedbutdevelopnosymptomsSomebecomeinfectedanddevelopmildormoderatesymptomsSomebecomeinfectedanddevelopseveresymptomsSomedieasaresultoftheirinfectionPathogenesisofinfectionClinicalmanifestationsofinfectiousdiseasesNon-specificOrgan system-basedFeverAnorexiaFatigueMuscleachesSkinrashastateofphysicaland/ormentalweaknessLossofappetiteMaryMallonwasanasymptomaticcarrieroftyphoidfever.Overthecourseofhercareerasacook,sheinfected53people,threeofwhomdied.Host-Pathogen Interactions:SymbioticRelationships1.Mutualism2.Commensalism3.Parasitism4.NeutralismAsymbioticrelationshipinwhichbothspeciesbenefitAsymbioticrelationshipinwhichoneorganismderivesbenefitandtheotherisunharmedAsymbioticrelationshipinwhichonespecies,theparasite,benefitsattheexpenseoftheother,thehostThestateofbeingneutral;neutralityprefix,avariantofsyn-beforeb,p,andm=Together=Life;livingorganismairborne infectiondroplet infectionvector-borne infectionwaterborne infectionbloodborne infectionModeofinfectionSneezingcanspreadthefluvirustootherpeople.airborne infectiononethatiscontractedbyinhalationofmicroorganismsorsporessuspendedinaironwaterdropletsordustparticles.droplet infectioninfectionduetoinhalationofrespiratorypathogenssuspendedonliquidparticlesexhaledbysomeonealreadyinfected(droplet nuclei).vector-borne infectioninfectioncausedbymicroorganismstransmittedfromonehosttoanotherbyacarrier,suchasamosquito,louse,fly,ortick.waterborne infectioninfectionbymicroorganismstransmittedinwater.Classificationofinfections1Type of the pathogenDegree of involvementBacterial,viral,fungal,parasiticLocal/focal,generalizedManner acquiredCommunity,hospital/nosocomialClassificationofinfections2Type of occurrenceEndogenous vs.exogenousAutoinfection vs.cross-infectionSuperinfection vs.reinfectionsepsisOpportunistic infectionaninfectioncausedbyaninfectiousagentthatisalreadypresentinthebody,buthaspreviouslybeeninapparentordormant.aninfectionthatdevelopsfrombacterianormallyoutsidethebodythathavegainedaccesstothebodyaninfectioncausedbyadiseaseagentthatisalreadypresentinthebodyaninfectionbyanorganismthatdoesnotordinarilycausediseasebutbecomespathogenicundercertaincircumstances(e.g.,impairedimmuneresponses).thetransmissionofacommunicablediseasefromonepersontoanotherbecauseofapoorbarrierprotectionaninfectionfollowingapreviousinfection,especiallywhencausedbymicroorganismsthathavebecomeresistanttotheantibioticsusedearlierasecondinfectionbythesamemicroorganism,eitherafterrecoveryorduringtheoriginalinfection12345678abacterialinfectioninthebloodstreamorbodytissues1.Cross-infection2.Exogenousinfection3.Endogenousinfection4.Opportunisticinfection5.Reinfection6.Superinfection7.Autoinfection8.SepsisLaboratorydiagnosisofinfectiousdiseasesGold standard testproceduresMicroscopyandStainingproceduresCultureandsensitivitySerologictestStainingproceduresUrinalysisandfecalysisSpecimensmear(blood,stool)GramStainingZeihl-NeelsonstainKOH(potassiumhydroxide)testforfungiGramStainingGram stainastainingprocedureinwhichmicroorganismsarestainedwithcrystalviolet,treatedwithstrongiodinesolution,decolorizedwithethanol,andcounterstainedwithacontrastingdye;thoseretainingthestainaregram-positive,andthoselosingthestainbutstainingwiththecounterstainaregram-negative.Zeihl-NeelsenstainTheZiehl-Neelsen stain,alsoknownastheacid-fast stain,wasfirstdescribedbytwoGermandoctors;FranzZiehl(1859-1926),abacteriologistandFriedrichNeelsen(1854-1898),apathologist.Itisaspecialbacteriologicalstainusedtoidentifyacid-fastorganisms,mainlyMycobacteria.nSpecimens mounted in 10%KOH and examined directly under the microscopeKOH(potassiumhydroxide)testforfungiCultureandsensitivitySerologictestanylaboratorytestinvolvingserologicreactions,especiallyanysuchtestmeasuringserum antibodytiter.TreatmentandpreventionMedical treatmentprophylaxisPre-andpost-exposurePharmacologicalImmunizationantibioticsvaccinationlocaltreatmentofthewoundadministrationofrabiesimmunoglobulinPre-and post-exposureprophylaxisAyounggirlinfectedwithsmallpox(1973).Duetothedevelopmentofthe,thediseasewasofficiallyeradicatedin1979.smallpox vaccineOutlinePathogenHostPathogenesisofinfectionClassificationofinfectionClinicalmanifestationsLaboratorydiagnosisofinfectiousdiseasesTreatmentandpreventionLEARN MORE,BE MORE