人体寄生虫学课件：总论（2013级本双语）

PARASITOLOGYMedicalINTRODUCTIONTOMEDICALPARASITOLOGY

MaintopicsParasitism,TypeofParasiteandHostLifecycleandInfectivestageTheRelationshipbetweenParasiteandHostFeatureofparasiticinfectionandparasitosisEpidemiologyofParasitosis

Abranchofthemedicalsciences.IsthesciencetostudytheparasiteandparasiticdiseasesAsciencetostudytheparasitism.Belongtonosetiology(病原生物学).Abasiccoursefortheclinicandphylaxiology(预防医学)MEDICAL(HUMAN)PARASITOLOGYPrefacemedicalhelminthology医学蠕虫学medicalarthropodology医学节肢动物学medicalprotozoology医学原虫学MEDICALPARASITOLOGYWhydowewanttostudyhumanparasit-ology?HARMFULNESSOFPARASITESTOHUMANBEINGSTenimportanttropicaldiseasesdefinedbyWHO:1975-1Malaria(疟疾)2Schistosomiasis(血吸虫病)3Filariasis(丝虫病,淋巴丝虫和盘尾丝虫)4Leishmaniasis(黑热病)5Trypanosomiasis(锥虫病,非州锥虫病和美州锥虫病)6Leprosy(麻风病)2000-7Tuberculosis(结核病)8Denguefever(登革热)疟疾血吸虫病丝虫病黑热病钩虫病我国五大寄生虫病疟疾血吸虫病丝虫病黑热病钩虫病

INCHINA

meaninfectiverate(%)(2004)(1990)Ascaris12.7247.3Trichuris4.6319.3Hookworm6.1217.2informationofparasiticinfectionsinChina

parasites:56species，

totalinfectiverateofhelminths21.74％

Theproblemandchallengewearefacedwithatpresent1.土源性线虫（钩虫、鞭虫、蛔虫、蛲虫）虽然得到明显控制，但仍然是主要问题2.食源性寄生虫病急剧上升3.机会性寄生虫、性传播寄生虫感染率增加4.新现寄生虫不断出现哇!寄生虫的危害如此之大!不说不知道,说了吓一跳耶!老师,这寄生虫是何许东西?好问题,且听我慢慢道来PARASITISMPARASITE&HOST1Fromviewpointsofbenefitandharm,thereare3kindofrelationships1.Commensalism（片利共生）:

anassociationwhichisbenificialtoonepartnerandnoharmtotheother.benefitNoharm&nobenefitTherelationshipsbetweenanimalsthatlivetogetherParasitism（寄生）:

Onepartnerderivesbenefit.Anotherisinjured.Parasitisminvolvestwofactors:parasiteandhostMutualism（互利共生）:

reciprocalbenefitbetweenthetwoorganisims.benefitbenefitbenefitBeinjuredparasitehostAmongthepartnersintheparasitism,theonewhichbenefitsfromtheotherisaparasite,whiletheonewhichisharmedbytheparasiteisahost.PARASITEandHOSTCLASSIFICATIONOFPARASITES

1.Basingonthebiologicaltaxonomy(1)Medicalprotozoa(2)Medicalhelminths(3)Medicalarthropods(1).Obligativeparasites:专性寄生虫(2).Facultativeparasites:兼性寄生虫(3).Endoparasite:体内寄生虫(4).Ectoparasite:

体外寄生虫.(5).Opportunisticparasite:机会致病寄生虫2.BasingontherelationshipbetweenparasiteandhostIntermediate

host(中间宿主):thoseprovidethelivingoflarvaeofhelminthorasexualstagesofaprotozoan.FirstandsecondintermediatehostReservoirhost

(保虫宿主):thoseanimalhostsofhumanparasitesinwhichparasitesarekeptaliveforlongperiodoftimewithfrequentexcretionoftheeggsorpathogens(serve

asasourceofinfectionforhumans).

Definitivehost(终宿主):thoseprovidethelivingofadulthelminthorsexualstageofaprotozoan.TypesofhostsTransportorparatenichost(转续宿主):LIFECYCLEOFPARASITES2Thewholebiologicalcourseofgrowth,developmentandreproductionofaparasite,includingenvironmentconditionsitneeds.Therearetwotypesoflifecycle:directandindirect.LifecycleDirecttypelifecycleDon’tneedintermediatehostIndirecttypelifecycleNeedintermediatehostThestagethatisabletoinfecthumanbodyinlifecycle.Iermediatehost.diagnosticstage.

infectivestage&transmittingpath.Lifecycleisacoreinparasitology.5.THERELATIONSHIPBETWEENPARASITEANDHOST3A.Uptakingnutrition（夺取营养物质）B.Physicaltrauma（机械性损伤）C.Chemical(toxins)andallergiceffects（化学性和免疫病理作用）:a)Lyticnecrosis:Enzymesb)Stimulationofhosttissuereaction:c)causinghypersensitivity1.EffectsofParasitesonHost

2.Effectsofthehostonparasiteimmunity(refertoimmunology)Resultsfromreactionbetweenparasiteandhost1Parasitewillbeeliminated2Keepbalance(suppressiveinfection,carrier)3Parasitosis4CharacteristicofParasiticInfectionandParasitosisdefinitionParasiticinfection寄生虫感染Parasitosis寄生虫病carrier,inapparentinfection带虫者,隐性感染Polyparasitism多虫寄生Larvamigrans幼虫移行

ectopicparasitism异位寄生Parasiticzoonosis人兽共患性寄生虫病Opportunisticpathogenesis机会致病CharacteristicofparasiticinfectionImmunityofparasiticinfection5featureComplicationofantigens(structure,stage,metabolism)2.Non-sterilizingimmunityiscommon:premunition(带虫免疫),concomitantimmunity(伴随免疫)3.Re-infectionoccursoften4.Immuneevasion(免疫逃避)5.

Eosinophilia

andIgElevelincreasewithinfectionofhelminthesEPIDEMIOLOGYOFPARASITOSIS6routeoftransmissionSourceofinfectionSubjectsofindividuals(orsusceptiblepopulation)parasite1.BasicconditioninparasiticepidemiologyA.patientsB.carrierC.reservoirhost

(1)Sourceofinfection(2)RouteofTransmissionA.Wayoftransmission(传播方式）Water-borne经水Food-borne经食物soil–borne经土壤Arthropod-borne经节肢动物Person-to-personcontact与人体接触Air-borne经空气B.Portalofentry(侵入途径）a.Oralroute经口b.Skinandmucousmembraneroute经皮肤黏膜c.Arthropodbite经节肢动物叮咬d.Person-to-personcontact经接触Transplacentalpenetration经胎盘Bloodtransfusion经输血Inhalation吸入

(3)SubjectsofindividualsorSusceptiblepopulation

Humansoranimalswhoareweaklyordefecti-velyresistanttocertainparasites.2.MajorfactorsinfluencingtheepidemicofparasiticdiseaesNaturalfactorweather,geographyetc.(2)Biologicalfactordistributionofintermediatehosts(2)SocialfactorsPolitical,economic,cultureandpersonalbehavioretc.3.Epidemiologicalfeatureofparasitosis

Endemicepidemic(地方性):

Theparasiticinfectionsusuallyfocusoncertainareas.

Reason:A.WeatherconditionB.DistributionofintermediatehostC.Resident’scustom(eatingorotheractivities)(2)Seasonalepidemic(季节性):

Epidemicofparasitosisisoftenseasonal.Infectiverateofsomeparasiteschangeinseasons.Reason:Temperature,rainingetc.caninfluencethegrowthofparasitesandactivityofvectors.(3)Naturalfocalepidemic(自然疫源性):

Someforestanddesertareaswheretheparasitic

zoonosescantransmitamongwildvertebrate,arecallednaturalendemicfoci.Ifsomeoneenteredthearea,heorshewouldgettheparasitic