蠕蟲（helminths）是一種軟體動物，借助肌內的伸縮而蠕動的多細胞動物其形態(tài)結構上的共同點是身體由上皮和肌內構成的皮膚肌內囊包囊，蟲體兩側對稱，器官分化PhylumNemathelminthes：ClassSecernentea(分腸綱）ClassAdenophorea（有腺綱）PhylumPlatyhelminthes:ClassTrematoda

(fluke)ClassCestoda(tapeworm)寄生在人體的蠕蟲引起的病，成為蠕蟲病Medicalhelminthology線蟲綱

1999年世界衛(wèi)生組織指出：“在熱帶和亞熱帶地區(qū)，土源性線蟲病和血吸蟲病帶來的損失占全部疾病負擔的40％以上。發(fā)病多見于兒童，常引起營養(yǎng)不良、貧血、生長遲緩、智力受損，極易患其它的感染等”。NematodesMorphology

themostwormlike,roundwormsalightcream-whitecolor,butthefemaleofthesmallerformsmayappeardarkerwhenfilledwithdark-coloredeggcontainabodycavity,orpseudocelom(nutrients)

Structure(bodywall)

cuticulalayer(角皮層)

subcuticularlayer(皮下層)

muscularlayer(縱肌層)（三）消化系統(tǒng)（四）生殖系統(tǒng)ACBA：meromyarian(少肌型)

例如：鉤蟲

B：polymyarian(多肌型）

例如：蛔蟲

C：holomyarian(細肌型)

例如：鞭蟲蟲卵幼蟲成蟲線蟲幼蟲發(fā)育中最顯著的特征是蛻皮therearethreemodesbywhichinfectionsistransmittedIngestion(mostoften)SkinpenetrationInsectbite

Lifecycle

蟲卵形態(tài)成蟲形態(tài)thelifecyclescoulddividedintodirectandindirecttypesbasisofwithoutintermediatehostorwithintermediatehost不需要中間宿主型：蟲卵或幼蟲不需離開人體而立即具有感染力蟲卵需在外界發(fā)育成感染期蟲卵具有感染力蟲卵需在外界發(fā)育為感染期幼蟲具有感染力雌蟲產出幼蟲經血流到肌內形成包囊而具感染力需要中間宿主型：幼蟲需在中間宿主或媒介體內發(fā)育為感染期幼蟲后由媒介叮人吸血時感染人體Microscopicexaminationoffecalspecimens糞便檢查DirectWetSmearwithsaline(直接涂片法)SedimentationConcentration(飽和鹽水浮聚法)Culture(培養(yǎng)法)：定量檢查

theCellulosetapepreparation(透明膠紙粘貼法、棉簽拭子法)PCR:PCR檢測,一個蟲卵即可診斷Diagnosis&Prevention:Sincethisinfectionissocommonandtransmissionissoeasy,preventionismarginal.Improvedpersonalandgrouphygienecombinedwithgrouptherapycanbehelpful.Undermostcircumstances,totalpreventionisneitherrealisticnorpossible糞管,注意環(huán)境衛(wèi)生、家庭衛(wèi)生、個人衛(wèi)生及防止相互感染治療病人和帶蟲者

Ascarislumbricoides(似蚓蛔線蟲),簡稱蛔蟲

Itisthelargestnematodeparasiteinthehumanintestine.

成蟲寄生在小腸，引起蛔蟲病(ascariasis)，有時可以進入膽道等臟器引起嚴重并發(fā)癥。MorphologyAdult:large&pinkworms

Ascarislumbricoidesfemaleworm:20to35cmmaleworm:30cm蟲卵egg

受精卵fertilizedegg

未受精卵unfertilizedeggBBBA受精膜殼質層蛔甙層Lifecycleunderfavorablecondihtionstheeggdevelopedtoinfectivestage

(蟲卵在外界發(fā)育)underanextraordinarymigrationthroughthebody(幼蟲在體內移行)成蟲在小腸寄生成蟲蟲卵含蚴卵感染性卵

產卵5-10days7days小腸壁V門V右心肺肺部微血管肺泡咽食道幼蟲移行途徑(60-75days)移行途徑：Maturefemalewormshavebeenestimatedtoproducedailyanaverageof240000eggsAfterinfectiveeggsareswallowed,thelarvaehatchinvadetheintestinalmucosa,andcarriedviatheprotal,thensystemiccirculationstothelungsThelarvaematurefurtherinthelungs(10-14days)thenpenetratethealveolarwalls.Duringthisstage,pulmonarysymptomscanoccurwithcough,andeosinophilicpneumonitis(Loefflersyndrome)肺部癥狀:X-RAY肺部浸潤影；血嗜酸性細胞增多；異位侵入PathogensisHelminthinfectionsinduceTh2responsesthatarecharacterizedbyeosinophilia.Antiparasiteantibodies(oftheIgEisotype)alsowereinduced.Larvae

stageAdultstageThelarvaeascendthebronchialtreetothethroatandareswallowed.WhentheyreachthesmallintestineanddevelopintoadultwormTheadultwormliveinthelumenofthesmallintestineAfemalewormmayproduceeggs,whicharepassedwiththefecesInyoungchildren,alargebolusofentangledwormsinthesmallbowelcauseabdominalpainandintestinalobstruction營養(yǎng)不良

過敏反應

常見并發(fā)癥(異位)MostpatientsremainasymptomaticAdultwormsrecoveredfromchildaftertreatmentwithmebendazole.Childwithdistendedabdomen(bolusofA.lumbricoidesadultsinsmallintestines)obstructadiverticulumobstructingofintrahepaticandextrahepaticbileductsBiliarytree:branchesofbileductintheliver.Theliverproducesbilewhichissecretedviatheductstotheintestinetoaidindigestionoffats.Pancreatitis:inflammationofthepancreasAdultascaris(arrow)inappendix.AstudybyCooperetal(2003)inEcuadorsuggestthatinfectionwithintestinalhelminths,particularlyascaris,protectsagainstthedevelopmentofseverinflammatorydiarrheainchildren.Thepossibleprotectivemechanismmaybetheproductionofantimicrobialsubstancesbythewormsortheincreaseinmucosalresistancethroughmodulationofthemucosalimmuneresponse.InfectionwithintestinalhelminthshasalsobeenusedasanexperimentalremedyforinflammatoryboweldiseaseSomeadditional?!

Laboratorydiagnosis---stoolexamination1.directwetsmear直接涂片法,2.沉淀法

3.sedimentofconcetrated飽和鹽水浮聚法

4.驅蟲治療性診斷Epidemiology世界性分布Ascariasisaffectsmoreoftheworld’spopulationthananyotherparasiticdisease—perhapsasmanyas1.3billionpersons.Thepercapitawormburdenmayreachhundreds,orevenathousandormoreinasingleindividual.Intheworldwideifplaceheadtotailthewormwouldencircletheworld50times!

感染率高的原因:產卵量大

生活史簡單

蟲卵抵抗力強生產生活方式

Treatment，Preventionandcontrolalbendazole：200mg(兒童)

400mg(成人)sideeffectareminimalmebendazole：100mgbid×3daysImprovedpersonalhygieneamongpeoplewhohandlefoodisanimportantaspectofcontrol

EnterobiusvermicularisEnterobiusvermicularis,thehumanpinworm成蟲寄生在盲腸、闌尾、直腸等處引起蟯蟲病(enterobiasis)。

MorphologyShortandwhitefusiformwormThemaleis2to5mmlongand0.1to0.2mmthickThefemaleis8to13mmlongand0.3to0.5mmthick感染期卵成蟲卵

幼蟲Lifecycletheeggmaysurviveforsomedaysindrydustairborneeggsmayinfectpersonatsomedistanceatypeofautoinfectiondescribedas“retrofection”Pathogensis是常見的小兒科疾病pinwormsortheireggshaveoccasionallybeenreportedfromotherectopicsites,suchasliverandlung

蟯蟲性闌尾炎

蟯蟲性泌尿生殖系統(tǒng)炎癥Diagnosis發(fā)現(xiàn)蟲卵或成蟲即可診斷從糞便中檢出蟲卵率低于5-15%？透明膠紙粘貼法、棉簽拭子法

Crosssectionofadultinappendix.crosssectionsofEnterobiusvermicularisinappendix

Epidemiology蟯蟲病是世界性分布的常見寄生蟲病傳播方式

1.經口感染直接或間接

2.吸入感染

3.逆行感染retrofectionPinwormisbyalloddsthemostcommonhelminthparasiteofthosetemperateregionswheresanitationmeasuresarerelativelyrigorousasmuchas10%ofthepediatricpopulationmaybeinfectedinthesearealessattentionispaidtopinworminthetropicalareas,probablybecauseoftherelativeprevalenceofmoreimportantparasites蟯蟲病分布廣泛的原因

生活史簡單

蟲卵抵抗力強，一般濃度消毒液不能殺死蟲卵

衛(wèi)生習慣不良Healtheducationonpersonalandcommunityhygieneandgroupchemotherapyconstitutethecontrolmeasure

(普治共治，集體治療)注意環(huán)境衛(wèi)生、家庭衛(wèi)生、個人衛(wèi)生及防止相互感染。治療病人albendazole：200mg(兒童)400mg(成人)mebendazole：100mgbid×3days

Topreventre-infection,treatthewholefamily.Treatment，PreventionandcontrolA3-year-oldgirlwasbroughttotheemergencydepartmentofageneralhospitalfollowinga3-weekhistoryofnausea,poorappetite,andabdominalpain.Shehadnothadanybowelmovementsforthelast2days.VS:T37°C,P110/min,R20/minBP102/54mmHgPE:Youngchildinmoderatedistressduetoabdominalpain.AbdomenwasdistendedandmildlytenderHematocrit:38%WBC4500/lDifferential:62%PMNs,23%lymphs,12%eosinophilesSerumchemistries;NormalToday’sCaseImagingX-raysofherabdomenwereconsistentwithintestinalobstructionHookwormHookworminfectioniswidelydistributedintropical&subtropical,wheretherearefavorableenvironmentalfactorforhookwormspreading,includingwarm,highrainfall,soilpollutionbyhumandefectionorfertilizationwithhumanfecesandpersonwalkingwithbarefeet.Hookworminfectionissecondonlytoascariasisasthemostcommonhelminthicinfection.HookworminfectionhasalmosteradicatedfromEuropeandUnitedStates.Ancylostomaduodenale(十二指腸鉤蟲)-----------thesmallintestineNecatoramericanus(美洲板口線蟲)--------------thesmallintestineAncylostomacerlanicum(錫蘭鉤口線蟲)-rarelyinfectshumanbeingsAncylostomacaninum(犬鉤口線蟲)-------rarelyinfectshumanbeingsAncylostomabraziliense巴西鉤口線蟲----creepingerupting,幼蟲可感染人，引起幼蟲移行癥

鉤蟲是一類口囊發(fā)達的線蟲，并在口囊內有銳利的切器，可損傷腸粘膜，吸食血液和組織液，使患者長期慢性失血，造成嚴重危害。鉤蟲寄生小腸引起鉤蟲Hookworminfectioniscontractedmainlybypenetrationoftheskinororalmucosabythefilariformlarvae(infectivestage)ofhookworm.Thus,barefootfarmersandchildrenwalkingoncontaminatedsoiloreatingcontaminatedvegetablesmaybecomeinfected.AdultsofA.duodenale

AdultsofN.americanusDifferencesbetweentwohookwormsMorphologyThemalewormisabout7to11mminlength&about0.4mmthickThefemaleislarger,9to13mmlongando.6mmthickFemaleshookworm:9-13mmlongwithegg-filleduterusMalehookworms:7-11mmlongPosteriorendformsacopulatorybursaAdult:theadultarecylindricalwiththeheadbentsharplybackwards,givingthemahookedappearance.Themouthofhookwormwerewelldeveloped,withapairofteethorapairofcuttingplate._____________________________________________________A.duodenaleN.americanus______________________________________________________Sizelargersmaller______________________________________________________Shapesinglecurve,lookslikeCdoublecurves,lookslikeS______________________________________________________Mouth2pairsofventralteeth1peirofventralcuttingplates____________________________________________________________CopulatorycircleinshapeovalinshapeBursa(2-3)(2-2)____________________________________________________________Copulatory1pairwithseparate1pairofwhichunitetoformspiculeendingsaterminalhooklet_______________________________________________________caudalspinepresentno_______________________________________________________vulvapositionpost-equatorialpre-equatorial_______________________________________________________TheMorphologicalDifferencesbetweenTwospeciesofHookwormsEgg(蟲卵)Eggoftwospeciesarenearlyindistinguishable.Theyareovoidwithathintransparentshelland,measure60mX40m,aclearspacethatseparatestheshellfromtheyolkcells.Thenumberofyolkcellsineggfoundinthestoolvariesfromtwotoeight.Larvaarhabditiformlarva(桿狀蚴):275X16m,thenewlyhatchedlarvafeedactivelyuponbacteriaandorganicdebris,growrapidlytoasizeof500to700min5daysafilariformlarva(絲狀蚴):slender,nonfeedingtheactivefilarformlarvafrequenttheupperhalf-inchofsoilandprojectfromthesurface-------infectivestage

頭端 扁平，中間微凹圓形，無凹陷

咽管矛不明顯 明顯

鞘膜橫紋不明顯 明顯

尾端 逐漸變細 驟然變尖 Ad絲狀蚴 Na絲狀蚴 十二指腸鉤蟲和美洲鉤蟲的分布/致病力/藥敏性各異Theysurvivebestinshadedlocalities,suchaslightsandyoralluvialsoilorloamcoveredbyvegetation,theyareprotectedfromdryorexcessivewetnessat0oClarvasurvivelessthan2wksat11oClessthan24hrsat45oClessthan1hrLifecycleHumansalmostexclusivelyarehostsforbothhookworm,whiledogsalsoarecommonhostforN.americanus.Wheneggsareexpelledwithfeces,underoptimalconditions(temperatureof23-33oC,shade,andsandysoilrichinorganicmaterial),arhabditiform-larvamaturesin1-2days&hatchesfromthethinshelledegg,feedsonbacteria&organicmaterialinthesoil.Aftertwomolts,itbecomesanon-feeding,infective,filariformlarva.

Finalhost:manInfectiveStage:Larva3orfilariformlarvaInfectiveRoute:byskin…Food:bloodandtissuefluidSiteofinhabitation:smallintestineLifespan:Ad15years,Na3-7yearsBlood-lungmigration:skin,cavumvena,rightheart,lungs成蟲卵桿狀蚴絲狀蚴（感染期）

經皮膚粘膜移行途徑皮膚小血管右心肺肺部微血管肺泡

食道咽小氣管Ad

保蟲宿主：豬、獅、虎、狗、猴Na

轉續(xù)宿主：猩猩、猴、犀牛等

成蟲寄生部位和攝食

Adultworminsmallintestine產卵量Ovaproduct

A.duodenaleproduces10000to

30000eggsperday

N.americanusproduces5000to10000eggsperday絲狀蚴具有向上性、向濕性、向溫性

character

of

filariformlarva:strongthigmotaxis,

moisture,thermotaxis(1-2cm)Penetrationskinororalmucosa(A.d),migration,developmentA.doffilariformlarvamayinvadehostskeletalmusculaturePathogenicity

鉤蟲感染鉤蟲病Thecourseofhumanhookwormdiseasecanbedividedintothreephases:

invasionphase

migrationphase

intestinalphase

Invasionphaselarvalinvasionofskin鉤蚴性皮炎itching,erythematouspapular,

vesiculareruption(withorwithoutedemaorenlargementoflymphnodes)secondarybacterialinfectioncreepingeruptionMigrationphase肺部損害themajorfeaturesarepulmonarymanifestationseverecases:

Loffler’ssyndromeorcoughing,dyspnea,pulmonaryinfiltrate,Eosinophilia,nausea,vomiting-----Wakanadisease

成蟲所致病變

消化系統(tǒng)的癥狀nausea,vomiting,abdominalpain,diarrhea,constipation--------intestinalcomplaints

慢性失血引起貧血anemia------bybuccalcapsule&‘teeth’toburrowthroughthemucosa,feedinguponblood

Intestinalphase貧血的原因：成蟲吸血：吸血量咬附部位粘膜滲血：咬附點滲血量蟲體吸血可以經常更換咬附部位，造成新的損傷，原傷口還繼續(xù)滲血

移位傷口滲血量造血物質吸收障礙；小細胞低色素性貧血Salivarysecretionsofthewormscontainanticoagulantsthatfacilitatebloodfeeding

A.d0.15

–0.26ml/worm/24hrs(3or6-8yrs)eggoutput10000to30000/dN.a0.03–0.05ml/worm/24hrs(3yrsor15yrs)eggoutput5000to10000/dKoilonychia(spoon-shapednails)duetoseverechronicirondeficiency.chlorosischildrenwithsevereinfectionshowsignsofproteinmalnutrition

(abdominaldistention,facialedema&hairloss)childrenwithchronichookwormanemia

physicalgrowthretardation deficitsinchildcognitionandintellectualdevelopment. reversedbyadministrationofanthelminthicdrugsprogressivecardiacinsufficiency-----congestiveheartfailure3mlto100ml/dayinmildorsevereinfection

另外與患者原來的健康狀況Geophagy(allotriophagy)(Pica):ahabitualingestionofnonfoodsubstances,oneofdiversecauseisirondeficiencyanemia(soil,wood,charcoal,paper)異嗜癥也許是鉤蟲病診斷的一個線索Infectionininfantorchildren---severestuntedgrowthdie嬰兒鉤蟲?。贺氀獓乐亍l(fā)育極差、合并癥多、死亡率高。經胎盤經乳汁經皮膚LaboratoryDiagnosis----------i