總論、腸道線蟲

1、人體寄生蟲學,Human Parasitology,醫(yī)學寄生蟲學(Medical parasitology) Medical parasitology，the study of animality pathogen動物性病原體 harming human health, is one of basic science of preventive medicine and clinical medicine. It stud

2、ies the pathogenic parasites寄生蟲 and their relationships to the hosts宿主 and environment. it consists of medical protozoology醫(yī)學原蟲學, medical helminthology醫(yī)學蠕蟲學 and medical entomology醫(yī)學節(jié)肢動物學.,A large mass of Ascaris lumb

3、ricoides that was passed from the intestinal tract.  The ruler at the bottom of the image is 4 cm (about 1.5 inches) in length.,,,S.japonicum:,,,WHO重點防治的寄生蟲病種類,瘧疾(malaria)血吸蟲?。╯chistosomiasis）絲蟲病(filariasis)利什曼病(

4、leishmaniasis)錐蟲病（trypanosomiasis）,寄生蟲病的流行和防治流行概況（國外）,世界衛(wèi)生組織確定的5種寄生蟲病Malaria ：90國，3億人感染Schistosomiasis ：76國，2億人感染,Filariasis ：76國，9000萬人感染Leishmaniasis ：非、美、歐、亞， 1300萬人感染Trypanosomiasis(錐蟲病)：非洲錐蟲病 30萬人感染美洲

5、錐蟲病 南美洲1800萬人感染,Malaria<30萬 Schistosomiasis約70萬(03年100萬) Filariasis 近期將被消滅 Leishmaniasis 300~400例/年 Hookworm disease2億多(3930萬),,流行概況（國內）,,,,,,,流行新趨向,1988年至1992年進行的全國寄生蟲分布調查結果表明，全國寄生蟲感染率高達62%。2004年感染率約為

6、52%。蠕蟲總感染率在21.74%，血清陽性率為25.59%食源性寄生蟲感染日益增多。機會致病性寄生蟲感染成為重要的問題。輸入性寄生蟲病已成一個不可忽視的問題。,我國重點防治的寄生蟲病,1.土源性線蟲?。夯住^、鞭蟲病2.食源性寄生蟲病：肝吸蟲病、肺吸蟲病、帶絳蟲病、囊蟲病、旋毛蟲病、弓形蟲病3.其它寄生蟲病：包蟲病、黑熱病,我國寄生蟲病流行情況,1.約5億人感染土源性寄生蟲(80%)，下降了約60%（與全國第一次普查）2.

7、食源性寄生蟲病上升、并向城鎮(zhèn)擴散，上升了75%（與第一次普查）3.囊蟲病在中、西、北部地區(qū)流行4.弓形蟲病呈擴大傳播趨勢5.包蟲病造成畜牧業(yè)巨大經(jīng)濟損失,,問題與挑戰(zhàn)1.土源性線蟲病防治工作與我國社會發(fā)展水平和文明程度不相適應2.食源性寄生蟲病已成為影響我國食品安全和人民健康的主要因素之一3.寄生蟲病對我國婦女和兒童危害嚴重(5~14歲人群中感染率最高，女性感染率高于男性)4.寄生蟲病嚴重阻礙西部地區(qū)的經(jīng)濟發(fā)展,一、寄生現(xiàn)

8、象(Parasitism),(一)共生 （symbiosis） Any organism that spends a portion or all of its life intimately associated with another living organism of a different species is known as symbiont 共生者, and the relationship is design

9、ated as symbiosis. 根據(jù)兩種生物間的利害關系，大致可分為共棲、互利共生和寄生三種現(xiàn)象。,1.共棲（commensalism),Commensalism共棲現(xiàn)象denotes an association that is beneficial to one partner and the neither benefited nor damaged to the other.（人 —— 結腸內阿米巴）,2.互利共

10、生（mutualism),Mutualism互利共生 is seen when such associations are beneficial to both organisms.（白蟻 —— 鞭毛原蟲）,3.寄生（parasitism）,Parasitism寄生現(xiàn)象is a symbiotic relationship in which one animal, the host宿主, is to degree injured

11、through the activities of the other, the parasite寄生蟲.Parasite usually is the smaller of the two organisms. （蛔蟲 —— 人）,（二）寄生蟲對寄生生活的適應,生理功能變化形態(tài)結構變化繁殖能力加強,(三)生活史 (life cycle)The parasitic life cycle is the obligator

12、y of parasites for their growth, development and multiplication that may be accomplished in their host (or hosts) or environment. 直接型生活史：不需要中間宿主間接型生活史：需要中間宿主,1.生活史過程,進入人體階段(或infection stage)在人體內階段(Migration and locali

13、zation stage)離開人體階段(Stage left man) 在外界環(huán)境或/和中間宿主的發(fā)育階段(Stage in environment /vector),2.感染期 (infection stage),The infective stage denotes a stage in life cycle of parasite, which can enter the human body and develop cont

14、inuously .（血吸蟲的尾蚴）,3.感染途徑(Route of infection):MouthSkinContactVector4.排離方式(Pattern left man ) StoolUrineBronchialSecretionVector,寄生蟲生活史模式圖,Stage in man（寄生部位）,Stage in environment,Stage left man,Infective st

15、age（感染期）,,,,,,人 體 內 移 行 途 徑,感 染 方 式 和 途 徑,排 離 方

16、 式 和 途 徑,二、寄生蟲的分類和類別,動物學分類寄生于人體的寄生蟲分隸于動物的5個門，原生動物門、線形動物門、扁形動物門、棘頭動物門和節(jié)肢動物門。（門、綱、目、科、屬、種）,學名的雙名制 (binominal system),屬名在前，用主格，詞首字母大寫；種名在后，用所有格，詞首字母小寫。(Plasmodium vivax),,(一

17、)寄生蟲的種類(types of parasite)1.專性寄生蟲、兼性寄生蟲(ecology)2.體內寄生蟲、體外寄生蟲(residing site)3.長期寄生蟲、暫時寄生蟲(duration)4.偶然寄生蟲、機會性致病寄生蟲（by chance and condition）,5.機會致病性寄生蟲： (opportunistic parasite)在宿主免疫功能正常時處于非致病的隱性感染狀態(tài)，當宿主免疫功能受損時，可

18、出現(xiàn)異常增殖和致病力增強使人致病的寄生蟲。（弓形蟲）,(二)宿主的類別(types of the host),1.中間宿主 (intermediate host)If the larval or asexual stage of the parasite develops.2.終宿主 (definitive host)If the adult worm or sexual maturity stage of the paras

19、ite develops.,3.保蟲宿主 (reservoir host) A vertebrate harbors parasite in nature and which serves as a source of infective organism for human. (肺吸蟲成蟲感染的狗和野生動物等),4.轉續(xù)縮主 (paratenic host) If a host acts as a transp

20、orting agent (vehicle) for the parasite and in which the parasite dose not undergo any development during waiting for an obligatory host, usually the definitive host (肺吸蟲幼蟲-豬),三、寄生蟲與宿主的相互作用 (host-parasite interp

21、lay),（一）寄生蟲對宿主的作用(harmful effects on the host)1.掠奪營養(yǎng)(Spoliatory action )2.機械損傷(Mechanical action) ：直接損傷或壓迫、阻塞3.化學毒性和過敏反應(Chemical and Immunopathological action )：ES等物質化學毒性作用和誘導免疫病理反應,(二)宿主對寄生蟲的防御(immune responses）,1.

22、先天性免疫皮膚、粘膜和胎盤的屏障作用吞噬細胞的吞噬作用補體系統(tǒng)激活后對蟲體的殺傷作用某些遺傳體質等,2.獲得性免疫,(1)消除性免疫 (sterilizing immunity)是指宿主能完全消除體內的寄生蟲，并能抵御同種寄生蟲再感染的免疫。（碩大利什曼原蟲-皮膚利什曼?。?(2)非消除性免疫(non-sterilizing immunity)寄生蟲感染后，宿主不能完全清除已感染的寄生蟲，可保持較低水平的蟲負荷狀態(tài)，但

23、具有抵抗同種寄生蟲再感染的免疫性。一旦寄生蟲完全清除，宿主的獲得性免疫也可隨之消失。（Premunition or concomitant immunity）,四、寄生蟲感染(parasitic infection),1.寄生蟲感染：寄生蟲侵入人體并在人體內寄生、發(fā)育，即構成感染。2.寄生蟲病人：寄生蟲感染后并產(chǎn)生臨床癥狀者3.帶蟲者(carrier)：有寄生蟲感染而無癥狀為帶蟲者。,4.隱性感染(suppressive infec

24、tion,感染寄生蟲后，沒出現(xiàn)明顯臨床癥狀，也不能用常規(guī)方法檢出病原體的寄生現(xiàn)象。（當宿主免疫功能受累時，蟲體大量增殖，致病力大為增強，甚至致死。）,5.幼蟲移行癥（larva migrans）,某些蠕蟲幼蟲侵入非正常宿主人體后，停留于幼蟲階段，可長期存活到處竄擾，難以定居，在竄擾移行過程中造成人體局部或全身性損傷。 內臟幼蟲移行癥 皮膚幼蟲移行癥,6.異位寄生（ectopic parasitism）,某些寄生蟲可在常見寄生部位以

25、外的器官或組織內寄生，引起異位病變。 蛔蟲、蟯蟲、衛(wèi)氏并殖吸蟲等,五、寄生蟲病的流行(epidemiology)(一)流行的三個基本環(huán)節(jié)（basic links）,1.傳染源(source of infection)被寄生蟲感染的人和動物: patient, carrier and reservoir host,2.傳播途徑(route of infection)寄生蟲從傳染源傳播到易感宿主的過程。 foo

26、d, soil土壤, air, insect vector昆蟲媒介 and so on.3.易感人群(susceptible of population)People who is non-immune and without any protection.,(二)影響寄生蟲病流行的因素,1.自然因素(natural factors)氣候、地理環(huán)境、生物種群、生物媒介、中間宿主和保蟲宿蟲等。2.社會因素(social fa

27、ctors)社會制度、經(jīng)濟狀況、生活習慣、生產(chǎn)方式、風俗和宗教信仰等。,（三）寄生蟲病流行特點,1.地方性(locally endemic)：環(huán)境、中間宿主、媒介昆 蟲2.季節(jié)性(seasonally endemic):媒介昆蟲季節(jié)消長、適宜生長發(fā)育環(huán)境條件3.自然疫源性(naturally endemic focal),自然疫源性的定義,在人煙稀少的荒野地區(qū)，某些寄生蟲可在脊椎動物間自然傳播（自然疫源地），當人進入該地區(qū)時，可

28、從脊椎動物傳給人，這種現(xiàn)象為自然疫源性。(肺吸蟲病在野生動物中傳播),六、寄生蟲病的防治原則,1.消滅或減少傳染源：治療病人和帶蟲者，治療或殺滅保蟲宿主。2.切斷傳播途徑：切斷任何一個環(huán)節(jié)都能終止傳播。3.保護易感染人群,,,Introduction to Protozoa,,General Account,Unicellular animal with full functionsDistribute widely: water

29、,soil, etc.Total species 65,000Free-living: majorityParasitic: about 10,000,Medical Protozoa,PathogenicOpportunistic parasiteNot normally pathogensBecome pathogenic due to impairment of host resistanceClinical

30、 importance of the AIDS epidemic,Basic Structures,Plasma membraneCytoplasmEctoplasm: locomotion & ingestionEndoplasm: metabolismNuclearVesicular form or compact formLocomotive organellePseudopodium, flagellu

31、m, cilia,Another example of a Giardia lamblia troph.  The two nuclei are easy to see in this image.,Tachyzoites of Toxoplasma gondii in macrophages of mouse in peritoneal exudate. (SEM),Mode of Reproduction,Asexual

32、 reproductionBinary fission: results in 2 daughter cellsSchizogony: multiple fission, results in multiple cellsEndodyogony: by internal budding results in 2 cells,Mode of Reproduction,Sexual reproductionConj

33、ugation: exchange of nuclear materials of 2 Gametogony : sexually differentiated cells unit ? zygote,Life Cycle Patterns,One stage formTrophozoite ( take food, be mobile, multiply)Two-stage form Trophozoite &am

34、p; cyst (not mobile, with cyst wall)Two-host formMammals : mammalsMammals : insect vectors,Characteristics of Protozoan in Infection,Proliferation-parasitemiaNo larva and adult differentiation but stage differencesM

35、ay be intracellular lodgmentOpportunistic & accidental infections (free-living),Medical Important Species,Amebae: 　　溶組織內阿米巴Flagellates：　杜氏利什曼原蟲，　　　　　　　藍氏賈第鞭毛蟲Sporozoites：瘧原蟲，弓形蟲Ciliates：　　結腸小袋纖毛蟲,Introduction to

36、 tromatodes,Phylum PlatyhelminthesClass TrematodaOrder Digenea,Morphology,Adult wormFlattened (flatworm) and leaf likeSucker: oral & ventral (fluke)Body wall: musculo-tegumental sacParenchyma (structure between

37、 body wall and internal organs): connective tissue fibers, cells and space between them,,Digestive tract: not intacti.e. no anal opening, caecumReproductive system: hermaphrodite (monoecious) exception of schistosome

38、Muscular systemNervous systemExcretory system,,EggSize divergentOvoidOperculum (exception of that of schistosome)Content: ovum , vitelline cells, or miracidium,Egg of Clonorchis sinensis,Egg of Paragonimus westerma

39、ni,Egg of Fasciolopsis buski,Features Reflecting Adaptation to Parasitism,Organs of attachment highly developedRetardation of digestive systemHighly developed reproductive system,Life Cycle,Complex Alteration of gene

40、rationsexual generation and asexual generation alter in the life cycle of parasiteAsexual multiplication in larval stage in snail hostMultiple hosts transfer and having reservoir hosts in majorityWater environment is

41、 essential,Important Species,Liver fluke: Clonorchis sinensisIntestinal fluke: Fasciolopsis buskiLung fluke: Paragonimous westermani P. skrjabiniBlood fluke: Schistosoma spp.,Introduction of Cestod

42、es (Tapeworms),Phylum PlatyhelminthesClass CestodaOrder PseudophyllideaOrder Cyclophyllidea,Morphology,Flat, segmented body with various length (several mm ~ several meters)3 regions of worm body:Scolex: suckers, ho

43、oklets, grooves Neck: germinal portionStrobila: immature, mature, gravid proglottids (segments),Taenia spp. adult wormThe chain of proglottids is called the strobila, and may be composed of over 1.000 proglottids. T.s

44、aginata may measure 9 m, whereas T.solium may reach 6 m.,Adult of Echinococcus granulosus,The scolex of T. saginata,,Monoecious (each segment): reproductive system highly developedDigestive system degeneratedAll specie

45、s are parasitic,假葉目絳蟲生活史,成蟲　　　蟲卵　　　鉤球蚴（終宿主）　　　　　　　　　　　　　　劍水蚤　　　　　　　　　　　　?。↖中間宿主）　裂頭蚴　　　　　　　原尾蚴　　　　　　蛙、蛇、人（II中間宿主）,,,,,,圓葉目絳蟲生活史,成蟲　　　蟲卵　　　中絳期　　　　　　　　　　　　囊尾蚴　　　　　　　　　　　　　　　　　棘球蚴　　　　　　　　　　　　　　　　似囊尾蚴,,,,,,,,,,,,,Intro

46、duction of Nematodes,Morphology,Adult worm The adults of nematodes are generally cylindrical圓柱形, nonsegmented 不分節(jié) and wormlike. Most medically important nematodes are dioecious雌雄異體 except the parasitic Strongyloi

47、des stercoralis 糞類圓線蟲. The males are generally smaller than the female worms.,Adulte of Ancylostoma duodenale andNecator americanus,Femelle,,Mâle,Mâle,Femelle,A.duodenale,N.americanus,Trichuris trichiura adult

48、s.,Microfilariae measure 270 by 8 ?m, have a sheath and a tail with terminal constriction, elongated nuclei and absence of nuclei in the cephalic space. They have nocturnal periodicity. (Wet mount preparation).,,Digesti

49、ve system Digestive tract is elongated and consisting of an oral cavity口腔, an esophagus食管, a midgut中腸 and a hindgut后腸 or rectum直腸, which opens in a subterminal anus.,Reproductive system,The male genital system is t

50、ubular and differed into a testis睪丸, a vas deferens輸精管, a seminal vesicle儲精囊, a small ejaculatory duct射精管 and a copulative apparatus交合器.The ejaculatory duct along with the rectum open into the cloaca泄殖腔,,The female worm

51、has two cylindrical ovaries卵巢, which expand into uteri子宮. The uteri may open to the exterior through a single vulva陰門, or there may be a common vagina陰道 between the vulva and uteri. The vulva is frequently located near t

52、he middle of the body but varies in position in different species.,,The eggs are ovoid, brownish and consist of three layers, which are lipid layer (ascaroside蛔甙層), chitinous shell殼質層 and fertilization membrane受精膜 (yolk

53、membrane卵黃膜) from inner to outer. Inside the eggs, there is commonly a embryo which may be a few blastomeres胚細胞 or a completely formed larva.,A. lumbricoides unfertilized egg.,Trichuris vulpis egg,Enterobius vermicularis

54、 egg. Note the thin shell and characteristic shape; approximate length = 55 µm.,Life cycle of nematodes,Stages in the life cycle of nematodes include the egg, larvae and adults. The larvae undergo several molts蛻皮, u

55、sually four times in the life cycle.,,The first molt and occasionally the second molt may take place in side the eggs, which are discharged by the host. Then the larvae develop into infective larvae with generally filari

56、form絲狀蚴 type of esophagus.,,,似蚓蛔線蟲,Ascaris lumbricoides,概述,人體最常見的腸道寄生蟲 寄生小腸的大型線蟲 生活史簡單，全球分布 我國:農(nóng)村>城市, 兒童>成人,A scanning electron micrograph of the anterior end of Ascaris showing the three prominent "lips,一、

57、形態(tài)(Morphology),1.Adult worm：體形，頭端唇瓣， 雄性尾部交合刺2.Egg：受精卵 感染期蟲卵 未受精卵,,Ascaris lumbricoides, fertilized egg.  Note that the egg is covered with a thick shell that appears lumpy (bumpy) or mam

58、millated; approximate size = 45~75 µm ×35~50 µm,A. lumbricoides unfertilized egg.,Ascaris lumbricoides infective egg.,A "decorticated," fertilized, Ascaris lumbricoides,二、生活史(Life cycle),Adult wo

59、rm Egg Larva Infective egg,,,,,移行,體外,發(fā)育,,（小腸）,Life cycle of Ascaris lumbricoides,蛔蟲生活史特點（1）,感染期與感染方式:口入感染性卵 體內移行:消化道-肺循環(huán)-消化道 寄生部位：小腸 發(fā)育：約2個半月 壽命：1年,蛔蟲生活史特點（2）,排離期與方式: 蟲卵隨糞便排

60、出宿主體外 外環(huán)境發(fā)育: 受精卵經(jīng)溫濕含氧土壤發(fā)育 2-3周為感染性卵,三、致病(Pathogenesis),Larva：蛔蚴性肺炎 (Loeffer’s symdrome) Adult worm：營養(yǎng)掠奪,機械損害, 超敏反應,嚴重引起外科 急腹癥,四、診斷(Dignosis),1.Etiologic examination: 糞便直接涂片法(method of first ch

61、oice)、Kato法2.蟲卵濃集: 離心沉淀法、飽和鹽水浮聚法,五、流行(Epidemiology),糞肥習慣 土源性生活史－簡單！ 產(chǎn)卵量大－24萬個/天/雌蟲, 蟲卵抵抗力強 傳播與個人衛(wèi)生有關,六、防治(Principles of control),預防為主：Fecal sterilization, Hygeinic education Drugs：Albendazole(阿苯達唑)

62、 400mg/頓服 甲苯達唑（Mebendazole） 100mg/次,2次/日，連服3日,,A.l. Parasitic site: small intestinal Infection stage:infective eggPathogenic stage: adult wormEtiologic dignosis:

63、 fecal direct smearDrug: Albendazole,蠕形住腸線蟲Enterobius vermicularis,一、形態(tài)(Morphology),Adult worm: 尾端尖細，中部膨 大,雄蟲尾端彎曲Egg: 透明,比鉤蟲卵小 兩側不對稱，一側稍凸 內含蝌蚪期胚胎,,Female adulte of Entero

64、bius vermicularis,Enterobius vermicularis egg. Note the thin shell and characteristic shape; approximate length = 55 µm.,二、生活史(Life cycle),Adult Egg

65、 Larva Infective egg,,,盲腸,結腸,雌蟲肛周,潮濕,6-8,小時,,,,,,生活史特點,寄生部位：成蟲于結腸排離方式：雌蟲肛周排卵感染期： 感染性卵(肛周6h)感染途徑：自身與異體感染,三、致病(Pathogenesis),肛周搔癢、繼發(fā)性炎癥異位寄生（Ectopic parasitism） ：

66、 泌尿生殖道,四、診斷(Dignosis),肛周采卵：肛門棉簽拭子法 玻璃膠紙法檢獲成蟲,五、流行(Epidemiology),兒童集居、家庭感染肛－手－口 自身重復感染吸入感染,,六、防治(Principles of control),預防為主集體治療、重復治療: Aldendazole,鉤蟲（Hook worms）,寄生人體腸道的中小型線蟲 我國五大寄生蟲病之一

67、 重感染致貧血 — 懶黃病 我國兩種人體鉤蟲,十二指腸鉤口線蟲Ancylostoma duodenale美洲板口線蟲Necator americanus,一 、形態(tài)（Morphology）,1.成蟲（Adult worm） 細長、頸彎、雌大雄小、 口囊發(fā)達 雄性尾部有交合傘,Adulte of Ancylostoma duodenale andNecator americanus,Femelle,,Mâle

68、,Mâle,Femelle,A.duodenale,N.americanus,,Crochet,Lame tranchante,,,A. duodénale,N.américanus,Capsule buccale,Scanning electron micrograph of the oral opening of Ancylostoma duodenale, another species of hum

69、an hookworm.  Note the presence of four cutting "teeth," two on each side.,兩種鉤蟲成蟲形態(tài)比較,十二指腸鉤蟲 美洲鉤蟲 體形 較大C形 較小S形口囊 具鉤齒 具板齒交合傘 圓形 寬型背肋 端部分叉 基部分叉交合刺 末端分離