医学寄生虫学：链状带绦虫 Taenia solium

1、链状带绦虫 Taenia soliumBrief introduction Pork tapeworm ，armed tapeworm。 Adult T. solium taeniasis猪带绦虫病Cysticercus囊尾蚴 cysticercosis囊尾蚴病/囊虫病humans can also serve as intermediate hosts1.Adult -StrobilaRibbon like, creamy in color 24m in length7001000 proglottids (节片)1.1 Scolex头节spherical 0.61mm in diamete

2、r4 suckers nonretractable rostellum ： with double crown of 25 to 50 prominent hooks 1.2 Neck颈节short ， 5-10 mm longthe budding zone containing germinative cells1.3 Mature proglottids成节 HermaphroditicSquare in shape150-200 testesA centrally straight uterus3 lobes of ovaryVitelline gland1.4 Gravid prog

3、lottid孕节713 lateral branches40,000 fertile eggs India Ink Technique2. Taenia egg31 - 43 mRounded or subsphericalBrown in colorThin,hyaline egg shell, Embryonic membrane胚膜Oncosphere 六钩蚴The eggs of Taenia saginata and T. solium are undistinguishable morphologically(morphologic species identification w

4、ill have to rely on the proglottids or scolices)3 Taenia solium cysticercus囊尾蚴 Larval form in tissuesElliptic bladder，0.61cm in diametermilky white, semitransparentfluid rich in albumin and saltsTaenia solium cysticercusinvaginated scolexScolex evaginates Cysticercus in muscle The infective stage of

5、 the parasite: can be found both in human and pigsin musclein liver in heart muscleCysticercusLife cycle Adult（In Human Intestine）Gravid proglottids(egg) （in feces）Oncospheres(Hatch out )invade the intestinal wall, and migrate to the striated muscles cysticerci （human、pig） Adult（In Human Intestine）（

6、eat raw pork, 23 months）Human cysticercosisRice porkbean-pork T. solium taeniasisdigestive juice hatch outPig or human eats eggs TAENIA SOLIUM life cyclecysticercosis ： faecal-oral ingestion of T. solium eggs oncospherecysticerci Adult :attaches the human small duce proglottids About 2

7、months after ingestion, proglottids begin to be excreted in the feces.The Lancet (2003) 361: 547Key points of life cycleDefinitive host: humanIntermediate host: pigs & humanInfective stage: cysticercus and egg Site of inhabitation: adult：human small intestine; cysticercus： in pig or human tissues In

8、fective route and mode: ingesting raw bean-pork or eggInfective mode of cysticercosis: Life span: 25 years; the cysticercus can survive 56 years in human body. internal autoinfection external autoinfection extrinsic infectionClinical propertiesAdult -Taeniasis: abdominal pain, anorexia, indigestion,

9、 diarrhea, emaciation, nervous disorder, urticaria, eosinophilia Cysticercus-Cysticercosis ： every organ and tissue can be involved. Most common :in the subcutaneous, connective tissues;Less common : eyes, brain, muscles, heart, liver, lungs, and coelom（体腔）. serverity of the disease depends upon:loc

10、ation of cysticerci Numbers of cysticerci.Cysticercosissubcutaneous type; ocular type; brain type1 Cysticercosis of subcutaneous tissue and muscleSubcutaneous nodulessmall and discrete swellings in muscle torso（躯干）, arms, legs, neck, face. movable and painless. muscular paincysticercus in the tongue

11、2 NeurocysticercosisCysticercus in brainEpilepsy (癫痫58-80% when parenchymal brain cysts)；Intracranial hypertension (颅内高压）, hydrocephalus (脑水肿，脑积水）, This syndrome is related to the location of parasites in the cerebral ventricles脑室or basal cisterns基底池. Three basic syndromes:convulsions（惊厥）, intracran

12、ial hypertension (颅内高压）, psychiatric disorderCysticercosis Cysts ： rounded or oval vesicles from a few mm to 1-2 cmMost common ：cerebral hemispheres( mainly at the junction of grey and white matter).Also found in the cerebellum小脑, ventricles脑室, brainstem, basal cisterns基底池, and spine脊柱.From: NEJM (2

13、001) 345:879Viable cysts.Cysts degenerate:CalcificationRacemose form:3 Ocular cysticercosisRetina （视网膜）, Vitreous body（玻璃体）Anterior chamber （前房）Impressions of shadows Secondary reactions: conjunctivitis(结膜炎）, retinitis（视网膜炎）, uveitis （葡萄膜炎）, atrophy of the choroid （脉络膜）Ocular cysticercosisDiagnosisT

14、aeniasis History Stool examination ：eggs；gravid proglottids Evacuation of the scolex following medication Cysticercosis History & clinical symptoms Biopsy of subcutaneous tissue or muscle Ophthalmoscope(眼底镜) for ocular type; X-ray, Computerized tomograph (CT) ，magnetic resonance (MR) for brain Serol

15、ogical examination for specific antibodySerologic diagnosis: IHA，ELISA，Dot-ELISANeuroimaging diagnosis: CT and MRIDiagnosis MRI showing parenchymal (A) and extraparenchymal (basal ccs) (B) viable NCC.MRI showing calcified cyst with surrounding edemaEpidemiologyWorldwide distribution but rare in Musl

16、im countries 27 provinces in China Yunnan Heilongjiang Jilin Shandong Henan HebeiEpidemiological factorsSanitation Pig husbandry pattern养猪业( Egg-contamination) Eating habitsRoutes to cysticercosisinternal autoinfection, external autoinfection, extrinsic infection云南民居在野外放养猪Treatment Parenchymal cysti

17、cercosis with viable cysts: Albendazole 15 (mg/kg/day) with dexamethasone (0.1 mg/kg/day). Praziquantel. Surgical therapy: ventricular shunting to resolve hydrocephalus. Also excision of giant cysts or intraventricular cysts Taeniasis treatment: praziquantelAlbendazoleIndividualized treatment based

18、on cyst location, level of inflammation and clinical presentationPrevention & control of cysticercosisChemotherapy： early treatment Control of pig husbandry Health education 云南白族制作“生皮”云南白族制作“生皮”肥胖带绦虫Taenia aginataBeef tapeworm ， unarmed tapeworm ,Similar to T.solium in life cycle & morphology. T.sag

19、inata TaeniasisNo human cysticercosisDifferentiation between T.solium and T. saginata1 strobila and proglottid 2-4m,700-1000segments，thin and transparent4-8m,1000-2000segments， thick and non-transparentT. saginatalive adult2 Differentiation between T.solium and T. saginataSquare up to 2 mm in diamet

20、er no rostellum and hookSpherical 1 mm in diameter two circles of hooklets( 25-50) on the rostellum3 Differentiation between T.solium and T. saginata2 lobes of ovary 3 lobes of ovary4 Differentiation between T.solium and T. saginata lateral uterain 713 branches on one side lateral branches15-30Gravi

21、d Proglottid of T. saginata5 Differentiation between T.solium and T. saginata Scolex with rostellum and hook, cause cysticercosis in humanScolex no rostellum and hook, not live in humanCysticercus in beef muscleTaeniarhynchus saginattus - cysticercus in the meatDifferentiation between T.solium and T

22、. saginataT. soliumT. saginataProglottid 2-4m,700-1000segs，thin and transparent4-8m,1000-2000seg， thick and non-transparentScolexSpherical, 1mm in diameter, with 4 suckers and hooklets Square, 2mm in diameter with,4 suckers but no hookletMature proglottid3 lobes of ovary2 lobes of ovaryGravid proglo

23、ttidlateral uterain 713 branches on one side1530 branches CysticercusScolex with rostellum and hookScolex no rostellum and hookIntermediate hostPig and man cattleTaenia life cycle Adult： human small intestine.DH：humanIH Eggs survive days to months in the environment Proglottids pass with stoolPathog

24、enesis of T. saginataHistopathology of Taenia saginata in appendix.Migration of proglottids out of the anus Most asymptomatic Abdominal pain, diarrhea, loss of appetite, weakness weight loss.Diagnosis and treatmentHistory of passing proglottids：first noticedStool examination ：egg.Recovery the scolex and gravid proglottid after treatment.Epidemiology and controlWorldwide distribution. Ingestion of raw beef containing the cysticercus. Chemotherapy with areca nut槟榔果plus pumki