蛔虫、鞭虫、钩虫(北大)课件

复习题？1.试述保虫宿主与转续宿主的区别。2.寄生虫为什么能在有免疫力的人体中生存而不被排除？寄生虫病的传播途径包括污染或含有寄生虫的感染期的土壤水食物节肢动物传播媒介√√√√寄生虫感染阶段是指寄生虫的：感染人体阶段感染保虫宿主阶段感染中间宿主阶段感染中间宿主阶段感染昆虫媒介阶段√人体寄生虫病的传染源包括：仅有病人和带虫者医学节肢动物

所有野生动物

病人、带虫者、感染的动物√关于蛲虫，下列哪项是错误的：1.生活史简单2.感染率儿童高于成人，城市高于农村3.生活史属间接型4.带虫者和病人是唯一的传染源5.感染方式主要是人群中的间接接触和肛门－手－口直接感染√AscarisLumbricoidesP162AscarisLumbricoides

Ascarislumbricoides,common

saying“roundwormofman”,isthelargestoftheintestinalnematodesparasitizinghumans.Itisthemostcommonwormfoundinhuman.Itisworldwideindistributionandmostprevalentthroughoutthetropics,sub-tropicsandmoreprevalentinthecountrysidethaninthecity

似蚓蛔线虫（蛔虫）Ascarislumbricoides♀♂一、形态成虫活体20~35cm15~31cm活体AdultwormofA.lumbricoides蛔虫唇瓣扫描电镜图“品”受精卵未受精卵脱蛋白质膜受精卵

虫卵蛋白质膜卵壳卵细胞新月形间隙卵黄颗粒成虫（小肠）卵随粪入土潮湿、荫蔽、O2充足21-30。C感染期卵经口误食、孵出幼虫、体内移行二生活史录像录像侵入肠粘膜的小V、小L右心门静脉肝肺肺泡（蜕皮2次）咽支气管气管食管胃小肠（蜕皮1次）蛔虫幼虫的体内移行：

1.

Siteofinhabitation:smallintestine2.Infetivestage:embryonatedeggs3.Routeofinfection:bymouth4.Nointermediateandreservoirhosts

5.Lifespanoftheadult:about1year

生活史的特点：III.Pathogenesis

Therearetwophasesinascariasis:1.Theblood-lungmigrationphaseofthelarvae:Duringthemigrationthroughthelungs,thelarvaemaycauseapneumonia.Thesymptomsofthepneumoniaarelowfever,cough,blood-tingedsputum,asthma.Largenumbersofwormsmaygiverisetoallergicsymptoms.Eosionophiliaisgenerallypresent.TheseclinicalmanifestationisalsocalledLoeffler’ssyndrome.2.Theintestinalphaseoftheadults.Thepresenceofafewadultwormsinthelumenofthesmallintestineusuallyproducesnosymptoms,butmaygiverisetovagueabdominalpainsorintermittentcolic,especiallyinchildren.Aheavywormburdencanresultinmalnutrition.Moreseriousmanifestationshavebeenobserved.Wanderingadultsmayblocktheappendicallumenorthecommonbileductandevenperforatetheintestinalwall.Thuscomplicationsofascariasis,suchasintestinalobstruction,appendicitis,biliaryascariasis,perforationoftheintestine,cholecystitis,pancreatitisandperitonitis,etc.,mayoccur,inwhichbiliaryascariasisisthemostcommoncomplication.录像致病（pathogenesis)录像1、幼虫致病2、成虫致病蛔虫性哮喘并发症掠夺营养

引起变态反应哮喘,荨麻疹并发症(国内报告8468例)胆道蛔虫症4556例(53.8%)蛔虫性肠梗阻2337例(27.6%)蛔虫性阑尾炎143例蛔虫性胰腺炎17例蛔虫性哮喘1352例蛔虫性肝脓肿33例直接涂片法四、诊断（diagnosis)改良加藤法录像五、流行与防治

(EndemityandPrevention)Worldwidedistribution,verycommoninChina,especiallyinthecountryside.Factorsfavoringthespreadofthetransmission:1.

Simplelifecycle.2.Enormouseggproduction(240,000eggs/day/female).3.Theseeggsarehighlyresistanttoordinarydisinfectants(duetotheascroside).

Theeggsmayremainviableforseveralyears.4.Socialcustomsandlivinghabits.5.Disposaloffecesisunsuitable.流行1.Treatmenttoascariasis:Mebendazole,AlbendazoleandLevamizoleareeffective.2.Sanitarydisposaloffeces.3.Hygienichabitssuchascleaningofhandsbeforemeals.4.Healtheducation.防治Trichuristrichiura(毛首鞭形线虫)1.Introduction:

Thecommonnameof

Trichuristrichiuraiswhip-worm(鞭虫),adultsliveincaecum(盲肠)ofhumanandresultintrichuriasis(鞭虫病)

2.Morphology:

1)Adultsresembleawhip,anteriorwithahair-likelashandposteriorwiththehandle.Mouthcavityisprovidedwithaminutespear2)Male:about4cmlong,posteriorisspirallycoiled.3)Female:about5cmlong,posteriorextremitystraight.

4)

EggAtypicalbarrelshapewithtwopolarplugs(2)Size:50-54µmby22-23µm

(3)Theexternallayeroftheshelloftheeggisyellowbrown(4)Anovumisintheeggwhenitpassedwithstool3.Lifecycleadults（cecum）

eggs1T~7T/dailymoist、warm3~5w

infectiveeggslarvae

（smallintestine）

adults

（cecum）

migrationdowncecumLarvaedonotentercirculationsystem！ingestion

4.PathologyFeedingontissuefluidandblood;Theslenderanteriorendspenetrateintothegutmucosaandmakelesions;Symptoms:Symptomsaredeterminedlargelybythewormburden:lightinfectionsareasymptomatic.Heavierinfectionsarecharacterizedby:1)chronicmucousandbloodydiarrhea2)abdominalpains3)hemorrhageandanemia(贫血)orrectalprolapse(直肠脱垂)inheavyinfectionchildren4)Theinfectionmayresultinmalnutritionandgrowthretardation5.DiagnosisDiagnosisisbasedonsymptomsandthepresenceofeggsinfeces6.PrevalenceandcontrolTrichuriasisoftenprevailwithascariasis17.38%ofpopulationinfectedwiththisparasiteinChinaThetreatmentandcontrolcanrefertoascariasis

十二指肠钩口线虫和美洲板口线虫（钩虫）(Hookworm)一、形态成虫♀♂♀♂十二指肠钩口线虫美洲板口线虫前进AncylostomaduodenaleNecatoramericanusand消化系统的特点：1、口囊发达2、咽管壁肌肉发达3、头腺、咽管腺分泌抗凝素、乙酰胆碱酯酶。大小体形口囊交合伞背辐肋十二指肠钩虫美洲钩虫“C”“S”两对钩齿一对板齿交合刺尾刺有无圆形扁圆形远端分两支，每支再分3小支基部先分两支，每支再分2小支♀:10~13x0.6mm♂:8~11x0.4~0.5mm♀:9~11x0.4mm♂:7~9x0.3mm前进十二指肠钩虫口囊美洲钩虫口囊实物扫描电镜图十二指肠钩虫口囊美洲钩虫口囊实物标本十二指肠钩虫交合伞美洲钩虫交合伞十二指肠钩虫背辐肋美洲钩虫背辐肋十二指肠钩虫背辐肋美洲钩虫背辐肋钩虫卵大小形状颜色卵壳内容物其他中等大小椭圆形无色透明4~8个卵细胞极薄卵壳与卵细胞间有透明间隙卵细胞透明间隙卵壳虫卵二生活史成虫（小肠）卵随粪入土潮湿、荫蔽、O2充足25~30。C杆状蚴经皮肤、体内移行、2次蜕皮、5~7周2次蜕皮丝状蚴（感染期幼虫）迁延移行二、生活史录像侵入皮肤小V、小L右心肺肺泡咽支气管气管食管胃小肠（蜕皮2次）钩蚴的体内移行录像生活史的特点：1、寄生部位：2、感染期：3、感染途径：4、感染方式：5、迁延移行：6、丝状蚴特性：7、转续宿主：小肠丝状蚴皮肤、口、胎盘、乳汁等接触泥土、生食蔬菜和转续宿主肉类、母婴传播等向温性、向触性猪、犬、灵猫等录像1、幼虫致病2、成虫致病三、致病（pathogenesis)钩蚴性皮炎“粪毒”钩蚴性肺炎哮喘腹泻和异嗜症贫血消化道出血嗜酸性粒细胞增多症婴儿钩虫病1、边吸血边排血；2、咬附部位渗血；3、更换咬附位置，原伤口仍渗血；4、虫体活动造成组织、血管损伤引起失血。钩虫引起贫血的原因：四、诊断（diagnosis)直接涂片法饱和盐水浮聚法钩蚴培养法优点缺点简便易行易漏诊检出率高，可鉴定虫种费时检出率高，较常用稍费时五、流行与防治

(EndemityandPrevention)

1.种植蔬菜与经济作物地区

2.用新鲜粪便施肥

3.种植时手脚接触泥土的机会多钩虫病流行的特点与原因五、流行与防治

(EndemityandPrevention)录像1、被钩蚴污染的尿布；2、睡沙袋、穿“土裤子”；婴儿感染钩虫的途径：3、经胎盘感染；4、经乳汁感染；钩虫病的防治

控制传染源

a).治疗钩蚴性皮炎:用左旋咪唑或15%

b)