医学寄生虫学：细粒棘球绦虫

1、1细粒棘球绦虫 （Echinococcus granulosus）2Brief introductionadult ：intestine of carnivoreslarval stages (hydatid) ：various mammalian intermediate hostshydatid cysts echinococcosis （棘球蚴病）, hydatidosis or hydatid disease(包虫病)Zoonosis3Echinococcus granulosus -the dog tape wormadult ： live in the intestine of d

2、ogsEggs are shed in the fecesEggs are infective to herbivores (and humans)41. Morphology1、Adults：27mm；one of the smallest tapewormsScolexshort neckStrobila: usually only three proglottids neckImmature proglottidMatureproglottidGravid proglottidimmature proglottidmature proglottidgravid proglottid56e

3、ggs of Taenia saginata, T. solium and Echinococcus granulosus are undistinguishable Eggs 7Hydatid Cyst棘球蚴Laminated layer角质层: 1mm, thick, outer, laminated, noncellular layerGerminal layer生发层: 20um, inner, thin, nucleated germinal layerbrood capsule protoscolex原头蚴 daughter/grand daughter cyst hydatid

4、sand棘球砂8infective stage for dogsHydatides usually grow slowly but steadily (1-5 cm per year)Cyst rupture or hydatid fluid leakage ： allergic reactions and metastasis(转移)Hydatid Cyst9The Hydatid Cyst10Life cycle Adult （intestine of canidae） Egg sheep/human oncosphere ingested gut Hydatid cyst liver/l

5、ungOffal is ingested by dog11Sites of hydatid1）liver（69.9%）2）lungs(19.3%)3）spleen, kidney, heart, bone, CNSLife cycle12Life cycle13Key points of life cycleDefinitive host: dog & other canine(intestine)Intermediate host: sheep, cattle, camel & humanInfective stage: egg ，hydatid cystHumans are infecte

6、d by Pathogensis stage: hydatid cyst Ingestion of and food/water contaminated with eggs Close touch with dogs14PathogenesisSeverity： location , size, number, growth speedSpace -occupying impairments Allergic reaction . Secondary infection 15Liver hydatidosisliver swelling, right epigastric pain, nau

7、sea, vomiting, discomfort, loss of appetite (anorexia)Midriff (横膈) moving up, dyspnea (呼吸困难) Obstruction of bile ducts and blood vessels Obstructive jaundice (阻塞性黄疸),cirrhosis and portal hypertension16 Lung hydatidosisObstruction & rupture chestpain, dry cough, bloody sputumdyspnea17 Abdominal hydat

8、idosisAscites (腹水)Obstructive jaundice (阻塞性 黄疸)Cholecystitis (胆囊炎)18Cerebral hydatidosis High infective rate children; focal epilepsy(局限型癫痫)headache,nausea, diarrhea, vomiting,hemiplegia (偏瘫)19Ocular hydatidosis 眼包虫病Osseous hydatidosis骨包虫病necrosis of bone, fracture of arm or leg20laboratory diagnosi

9、s Diagnostic puncture is forbidden!History ： contact with sheep & dogsClinical manifestationsX-ray，ultrasound，CT，MRI Definitive diagnosis：Demonstration of protoscolices or hydatid cysts in urine, sputum, ascites(腹水), or by operation. Serological examination for specific Ab or Cag 21Global distributi

10、on of E. granulosa (black) and E. multilocularis (x Epidemiology22Epidemiology Northwest sheep-raising area; Morbidity in china ：0.6% 4.5%; Factors of prevalence: high resistance of eggs; close relationship between humans and dogs domestic animals and dogs23Definitive host Intermediate host蓄粪烧炕24Tre

11、atment and controlSurgical treatment Hydatid is often injected with sterilizing fluids to avoid “metastases”Chemotherapy ：Praziquatel and albendazole are effective for early small cysts.Control of feral dogs, limit access of dogs to sheep offal, treat pet dogs regularly25(Echinococcus multilocularis

12、)多房棘球绦虫 Adult ： mammals (fox) larval stage ：human alveococcosis (泡球蚴病,泡型包虫病).26Echinococcus multilocularis - the fox tape worm Ingestion of contaminated berries and mushrooms collected in forests with foxesSylvatic zoonosis in Europe and northern AmericaFox ：final hostlife cycle similar to E. granul

13、osus27E. granulosus & E. multilocularis28 hydatid cyst and alveolar cystEchinococcus granulosus Echinococcus multilocularis Slow development of cyst Rapid development of cyst Cysts have thick-walled chambers Cyst has thin-walled chambersSeparated by connective tissue Not separated by connective tiss

14、ue Cyst is fluid filled Cyst is gelatinous filled 29Liver original Hydatid grows like a sponge through entire liverSymptoms are serious and similar with liver cancer Metastases ：in lung or brainHigh mortalityNo effective therapyEchinococcus multilocularis Pathogenesis30 EGranulosus E. multilocularis

15、 Length 27 mm 1.23.7 mm Scolex similar, with sucker , rosetellum and hooklets Segments 3 45 Metacestode hydatid cyst alveolar cyst IH sheep,yak,human rodent,yak,sheep,human DH dog (canidae) fox, wolf, dog31Questions:Why can you acquire human cysticercosis after ingestion of pork with T. Solium cysticercus? If you ingest some eggs of T. Solium, can you be diseased with human cysticercosis? If yes, why?Important words:tapeworm, c