1传染病学总论全英班

DepartmentofInfectiousDiseasesThirdhospital,SunYet-senUniversityPro.fGaozhiliang

GENERALPRICIPLESOFINFECTIOUSDISEASES1

SINGNIFECANCEANDIMPORTANCE

2HistoryreviewIn14thcentury,PlagueinEuropean,20millionpeopledeath；In17~18thcentury,smallboxinEuropean，150millionpeopledeath；In1918,fluintheworldwide，40millionpeopledeath。3In1905,NobelgainerofphysiologyandmedicineawardRobertKoch(Germany)Kochdiscoveredtubculosisbacilii4In1945,Nobelgainerofphysiologyandmedicineaward

AlexanderFleming(Scotland)In1928年，FlemingDiscorveredPenicillinIntoantibioticsera5WHOreports：

Among52millionofdeathintheworldwideannually,17million(32%)ofdeathfrominfectiousdiseasesandparasiteIndevelopingcountry，ahalfofdeathbyinfectiousdiseases；About15millionofdeathbyinfectiousdiseasesperhourintheworldwide，mostoccurredindevelopingcountry。6PatternofInfectioninDevelopedCountriesIn20thcentury,fallintheincidenceofcommunicablediseasesindevelopedcountriesduetofactorssuchas:Immunizationantimicrobialchemotherapyimprovednutritionandbettersanitationandhousing.7Re-emergenceofoldinfectiousdisease◆(Tuberculosis)

◆(Viralhepatitis)

◆(Sexuallytransmitteddiseases)

◆others:

cholera、charcoal8Re-emergenceofoldinfectiousdisease2milliondeathofTBintheworldwideannually7～8millioninfectedbyTBintheworldwideannuallyMarch24,for

WorldTBDay9Emerginginfectiousdiseases

WHOinformationnear30years,about30kindsofinfectiousdiseasesdiscoveredintheworldwide“Emerginginfectiousdiseases〞10Emerginginfectiousdiseases40millionofHIV/AIDScases

worldwideHIVinfectionrates:11cases/minute16000persons/perday6millionpersons/annually。95%indevelopingcountryMaximalnation:Africa,infectionrateabout10%Dec.1for

WorldAIDSDay

11EmerginginfectiousdiseasesSARS〔SARS—CoV〕From2002.11.16to2003.7，SARSspreaded6continent,32countries，casesof8437，deathof916Inchina,casesof5327，deathof349SARS:mostseriousemerginginfectiousdiseasesin21century12EmerginginfectiousdiseasesAvianinfluenza

H5N1virus

H1N1VIRUS13AntibioticsAntibiotics,withinthelast60years,ResultedinthecureofmanypreviouslylethalinfectionsOnlyseveralyears,drug-resistantemerged.pathogenicstaphylococciwerefoundtohavetheabilitytoproduceenzymes(penicillinases)thatdestroyedpenicillin,thusrenderingthedruguselessagainstthesestrainsOveruseandmisusemakethemuseless.14COMMUNICABLEDISEASESINFECTIONANDIMMUNITYPATHOGENESISEPIDEMIOLOGYDIAGLOSIS

TREATMENT

PROVENTION

PROFILE

15CONCEPTOFCOMMUNICABLEDISEASESCausedbypathogens:virus、chlamydia、richettsia、prion、bacteria、spirochete、fungusandparasite〔helminth、protozoa〕ormedicalinsectInfectiousdisease:involveanyorganorsystemofthebodyandthusembracesallmedicaldisciplines.Communicabilitywhichdifferentiatesinfectionsfromnon-infectiousdiseases.Transmissionofpathogenicorganismstootherpeople,directlyorindirectly,mayleadtoanepidemic.16

Infectionandimmunity

17一.ConceptofinfectionThecourseofstrugglebetweenpathogensandhumanoranimalbodies(host).Absolutelynecessarycondition18CommensalsopportunisticinfectionPrimaryinfectionRepeatedinfectionMixedinfectionSuperinfectionSecondaryinfectionKindsofinfections19Commensalism

Pathogensliveinthehost

butdon’tinducepathologic

changes.

Escherichiacoliinthecolon

Epstein-Barrvirus20Opportunisticinfection:

Pathogenswithinthehostcaninducepathologicchangesifhostimmunityissuppressedbysomefactors.

Cryptococcusneoformans

Cytomegalovirus

Candidaalbicans21Primaryinfection:measles,chickenboxRepeatedinfection:malaria,schistosomiasis,ancylostomiasisMixedinfection:rareSuperinfection:HBVoverlapHEVSecondaryinfection:HBVfollowing

bacilli22Eliminatepathogeninapparent/sub-clinicalinfectionapparent/clinicalinfectionCarrierstatusLatentinfectionInfectionsstatus〔infectionspectrum〕Entranceandcolonizationofpathogenswillleadtothefollowingresults23㈠Elimination:

pathogenswereexcludedoutbyhostnonspecificorspecificimmunity.

Suchas:Candidaalbicans

HepatitisAvirus24㈡inapparent/sub-clinicalinfection:

mostfrequentlyoccursin

healthyindividuals.

Theoutcomeswillbe:

A.Immunityacquired.HAV

B.Carrierstate:healthycarriers.HBV25㈢apparent/clinicalinfection

:

Theoutcomeswillbe:

A.Recovery.Shigella

B.Chroniccarrier.

Salmonellatyphi26㈣Carrierstate:

Definitionofdifferenttypesofcarriers:

.incubationcarrier

.acutecarrier

.convalescentcarrier

.chroniccarrier27㈤Latentinfection:

Afterinfection,pathogensremainlatentinsidethebody.

Developclinicalmanifestationswhenthehostimmunityhasbeenimpaired.

Pathogensusuallywillnot

beexcretedbythehostduringperiodoflatency.Herpessimplex28Theinfectionstatusmaychangeeachotherinsomeconditions.Latentinfection

ApparentCarrierstatusInapparenteliminatefrequency/ratio

29三、RoleofPathogensinInfectionProcess:

⑴Invasiveness:adhesion,

penetrationability.Shigella

⑵Virulence:toxins,enzymes,and

histolyticability.E.histolytica

⑶Infectiondose:minimaldose

thatcancauseaninfection.S.typhi

⑷Variability:changeinstructure

ofthepathogentoevadefromhost

immunity.Influenzavirus30四、

TheRoleofImmuneResponseinInfectionProcess:

Differentiationbetweenprotectiveimmunityandallergy.

.Protectiveimmunity:beneficial

.Allergy(anaphylacticreaction):harmful31⑴Nonspecificimmunity:

A.Naturalbarriers:

external(skin,mucousmembrane,cilia),internal(blood-brainbarrier).

B.Phagocytosis:monocytes,macrophages,andgranulocytes.

C.Humoralfactors:

complements,lysozyme,interferons(αβγ),cytokines32⑵Specificimmunity:

Immunerespondtospecificrecognizableantigens.

A.Cell-mediatedimmunity:

Importantinintracellularinfectionsbyviruses,fungi,protozoaandcertainbacteria.

B.Humoralimmunity:

Differentkindsofantibodies

(immuneglobulins,ADEGM)andtheirfunctions.33PathogenicMechanismsofInfectiousDiseases

34Establishmentanddevelopmentofinfectionprocesscanbedividedintothreestages1.

Portalofentry:

Eachpathogenhasitsspecificportalofentry.

Mycobacteriumtuberculosis,

Meningococcus----viabreathtract.

Shigella---viadigestivetract.352.localizationandDisseminationinthehost:

Specificforeachpathogen.

.Mumpsvirusinparotidgland.

.HepatitisCvirusintheliver.

.Shigellaintheintestine.363.Channelsofexcretion:

Importantfactorforhostinfectivity.Asthesourceofinfection.

.HepatitisAinthestool.

.HepatitisBintheblood.

.Measlesvirusinexpiratoryair.37二、MechanismofTissueDamages

1.Directinvasion:Cytolysis,tissuenecrosis,

inflammation.

2.Theactionsoftoxinsandcytokines:

Resultinginsepticshock,Disseminated

intravascularcoagulation,DICetc.

3.Immunopathogenesis:

Immunosuppression,T-celldestruction,

immunecomplexesinducecytotoxicities.38二、ImportantPatho-physiologicChangesininfection391.Fever(pyrexia):

Exogenousandendogenouspyrogens.

.Exogenouspyrogens:virusetc.

.Endogenouspyrogens:IL-1,IL-6,TNF,interferonetc.402.Metabolismchanges:

(1)Proteinmetabolism:

higherproteinscatabolism.

(2)Carbohydratemetabolism:

accelerationofglucolysis.

(3)Waterandelectrolytesmetabolism:

dehydration,hypokalemia.

(4)Endocrinedisturbances:

higheranabolism,

hyper-corticosteroidemia41

EpidemiologicalProcessofInfectious42EpidemiologicalProcess(course)include:

1.Sourcesofinfection:Human,animal.

⑴Patients:acute,chronic;

typical,atypical(mild,severe).

⑵Subclinicalinfection:

nosymptoms.poliomyelitis.

⑶Carriers:

chronic:typhoid,shigellosis.

⑷Infectedanimals:(naturalsource)

rabies,plague,schistosomiasis.432.Routesoftransmission

⑴Air,droplets,dusts:

e.g.measles,diphtheria.

⑵Water,food,flies(fecal-oral

infection):

e.g.typhoid,cholera.

⑶Fingers,utensils(contact

infection):

e.g.shigellosis,influenza.44⑷Arthropods:

A.Biologic:

intermediatehosts,

e.g.mosquitoesinmalaria,

chiggersinscrubtyphus.

B.Mechanical:

passivetransfer.e.g.fliesinamebiasis45⑸Blood,bodyliquidtransmission

SuchasHBV,HIV⑹Verticaltransmission:mothertobaby⑺Horizontaltransmission:others463.susceptibilitySusceptibleperson47二、FactorsInfluencing

EpidemiologicalProcess48Naturalfactors:

.Climatic:season,rain,humidity.

.Geographic:endemicity,

schistosomiasis

clonorchiasis

sinensis:freshfish2.Socialfactors:

Socialsystem,

social-economiccondition,

culturalbackground49

CharacteristicsofInfectiousDiseases

501.Basiccharacteristics:

(1)Presenceofpathogens.

(2)Infectivity:durationof

infection,chroniccarrier.

(3)Epidemiologicalfeatures:

age,sex,season;importedor

endemic;sporadicor

epidemicandpandemic;

epidemicoutbreaks.

(4)Post-infectionimmunity.512.ClinicalCharacteristics:

⒈incubationperiod

theperiodbetweentheinvasionofthetissuesbypathogensandtheappearanceofclinicalfeatures

⒉prodromalperiod

fromonsetofdiseasestoapparentclinicalfeatures52⒊Symptomaticperiod.

Apparentofclinicalmanifestations.

⒋convalescentperiod

lightenanddisappearclinicalmanifestations,Lab.normal53relapse

re-appearsymptomafterrecoveringofdiseases.S.typhirecrudescence

re-increasingandre-appear,whenlightingofclinicalsymptomanddecreasingoftemperature.S.typhi.54⒍sequela

bodyfunctionabnormalafterrecoveringofdiseases55Characteristicofinfectiousdisease563.Commonsymptomsandsigns.

⑴Fever(pyrexia):

A.Effervescence:earlystage.

B.Fastigium:full-blownstage.

C.Defervescence:

improvementstage57Feverforms

A.Sustainedfever:

Differenceofbody

temperaturelessthan

1degreecentigrade

within24hours,over39℃.

e.g.Secondweekoftyphoid58sustainedfever59B.Remittentfever:

Changeofbodytemperature

morethan1degree

centigradewithin24hours,

thebaselinehigherthan

normal.

e.g.Septicemia.60remittentfever61C.Intermittentfever:

Fluctuationbetweennormaltemperatureandhighfeverwithin24hours.

e.g.Malaria.62intermittentfever63D.Relapsingfever:

Feverlasting5~7days

withrelapseafterseveraldays.

e.g.Relapsingfever,

brucellosis.64relapsingfever65E.Irregularfever:

Curveofbodytemperature

isirregular.

e.g.Brucellosis,septicemia66⒉Skinrashoreruption:

67Noteappearancetypeanddayofthedisease.

Eraptiontime:firstday:chickenbox.secondday:scarlatinathirdday:smallbox.forthday:measles..Fifthday:shipfeversixthday:typhoidfever68A.Enanthem:

Rashonmucousmembrane(mucosa).

e.g.Koplikspotsinmeasles.B.Exanthem:

Rashonskinsurface,

e.g.chickenpox,smallpox.C.Maculopapularrash:

e.g.Maculaandpapule

(Maculopapule)in

measles

rosespotsin

typhoidfever.69macula70papule71herpesandpustule72d.Urticaria:Seenin:serumsickness,

tetenusantitoxin(TAT)parasiticdiseases,

schistosomiasisdrughypersensitivity,

piperacillin,etc.73(3)Toxemicsymptoms:

A.Generalpresentations:malaise;headache;anorexiapaininmuscles,jointsandbonesdisturbanceinconsciousnessMeningealirritationsepticshockLiverandkidneyfailure,etc.74B.Mononuclear-phagocytesystem(Reticulo-endothelialsystem)reactions:

hepatomegaly,

splenomegaly,

lymphadenopathy.754.Clinicalforms:

(1)development:Acute,subacuteandchronicforms.

(2)formsofclinicalmanifestation:

mild,moderate(typical)orsevereforms.

ambulatoryformintyphoid

(withoutsymptomandsigns).76AcuteFever;anoxia,acute-phaseproteinresponse,albuminaemia,lowserumiron,anemia,neutrophiliaInflammation:pain,dysfunction,tissuedamageConvulsion;especiallyinchildrenShockHemorrhage:hemolyticanemia,intravascularcoagulationOrganfailure:kidneys,liver,lung,heart,brain,necrosisofskin77ChronicWeightlossandmuscle-wastingMalnutrition:especiallyassociatedwithdiarrheaRetardationofgrowthandintellectinchildrenAnemia:ironsequestrationTissuedestruction:e.g.lunginpneumoniaortuberculosis,liverinhepatitisBPost-infectivesyndromes:e.g:post-viralfatiguesyndrome78

DiagnosisofInfectiousDiseases

79Clinicalmanifestations

(1)Modeofonset

(2)Typeoffever

(3)Accompanyingsymptoms:

headache,myalgia,arthalgiaetc.

(4)Signs:

Consciousness,jaundice,skinrash,

Koplikspot,eschar,subcutaneoushemorrhage,

liver,spleen,lymphnodes.80PathoghomonicsignsMeasles:KoplikspotsMumps:swellingofparotidglandScrubtyphus:escharLeptospirosis:myalgia,calfmuscleTyphoid:rosespotsCysticercosis:subcutaneousnodulesHepatoencephalopathy:flappingtremorShigellosis:mucus-pus-bloodystoolAmebicdysentery:strawberryjam-likestoolRabies:hydrophobia812.EpidemiologicalData:

(1)Historyofcontactwith

similarcases.

(2)Occupation,living

environmentandlifestyle.

(3)Historyofvaccination.

(4)Historyoftransfusionof

bloodorbloodproducts.82三、LaboratoryExaminations:

(1)Routineexaminations:

blood,urine,stool.

Leukocytosis,leukopenia,

eosinopenia,eosinophilia.

liverfunctions

kidneyfunctions,etc.83Leukocytosis:Infectionwithvirus:epidemichemorrhagicfeverJapaneseBencephalitisinfectiousmononucleosisrabiesInfectionwithbacteria,etc.84(2)Detectionandisolationofpathogens:

A.Directexamination:malariainbloodslides,choleraeinstool,diphtheriainthroatswab,Entamoebainrectalscrape,schistosomeovainrectalsnip,rickettsiainrashaspirate,fungiinskinscrapings,pneumococciinpurulentsputum,leprosybacilliinslitskinsmearByelectronmicroscopy:virusesinstool;herpesvirusesfromskinByhistologyofbiopsyspecimen;acidfastbacilliinleprosyandtuberculosis,hepatitisBinliver,rabiesvirusinbrain85B.CultureFromblood:typhoid,brucellosis,Gram-negativespeticaemia,pneumococcalpneumonia,HIVFrombonemarrow:tuberculosis,brucellosis,histoplasmosisFromotherbodyfluids,fecesortissues:urinarytractinfection,bacillarydysentery,sputuminpneumonia86C.AnimalinoculationIntraperitonealinoculation:

Rickettsiatsutsugamushi.Intracerebralinoculation:

encephalitisvirus.87D.SpecificImmunologicaldetection:Detectionofmicrobialantigen(blood,cerebrospinalfluid,sputum,urine)DetectionofantibodyofIgMclasse.g,hepatitisADemonstrationofantibodyRisingtitre:typhoid,brucellosis,HIVinfectionSkintesting:Tuberculosis,histoplasmosis,Nonspecific88F.Molecularbiologicassay:

Usingisotopeornon-isotopeprobes;

Polymerasechainreaction(PCR).

hepatitisCvirus,etc.89

㈢otherexaminationXray:lobarpneumonia,renaltuberculosis,muscularcysticercosisIsotope:detectionofabscessUltrasound:abscesshydatidcystComputedtomography(CT)ormagneticresonanceimaging(MRI):intracranialinfection,visceralabscesses90

TreatmentofIn