医学寄生虫学：曼氏迭宫绦虫

1、Spirometra mansoni曼氏迭宫绦虫Sparganosis裂头蚴病larva of spirometra tapeworm. Adult ：intestine of dogs, cats, /tigers,foxes, and allied species. Human acts mainly as the intermediate host.Brief introductionPhylum: Platyhelminthes(flatworms)Class: Cestoida绦虫纲Order: Pseudophyllidea假叶目Family: Diphyllobothriidae

2、裂头科Genus: Spirometra迭宫属Species: Spirometra mansoniMorphology Adult: 0.61m. head ： slim and finger-shaped, holdfast ： longitudinal bothrium. 1000 segments, each one is equipped with reproductive system (including uterine pore )Morphology Plerocercoid (Sparganum裂头蚴): 300 mm 0.7 mmwhitish, ribbon-shape

3、d transversely wrinkled, unsegmented strobila a scolex similar with that of adult wormbothriums75276m，3144mOperculumThin egg shell Immature when ovipositedEgg Adult（cat、dog） egg （stool） watercoracidium 2-5 wCyclops swallow procercoid3-11days SparganumCyclopstadpolefrog （human、cat、dog） Adult（cat dog

4、human ）Snake bird human(transport host)SparganosisLife cycle9Coracidium钩球蚴Procercoid 原尾蚴Sparganum裂头蚴plerocercoidCyclops 剑水蚤Tadpole 蝌蚪 第一中间宿主Cyclops（剑水蚤）Transport host 转续宿主 Life cycleDefinitive host: cats, dogs, carnivore1st intermediate host: Cyclops sp2nd intermediate host:frogtransport host: snake

5、， birdBoth procercoid原尾蚴and plerocercoid裂头蚴are infective to humans.Drinking raw water contaminated with procercoid Eating raw or poor-cooked flesh of frogs infected with SparganumUsing fresh flesh of frogs or snakes as a poulticeKey point of life cyclePathogenesis larval ：migrate into subcutaneous t

6、issue, eye, and brain. Death of the Sparganum intense local reaction.Symptoms and signs: irregular ，painful ，migratory inflamed skin nodules Oedema(水肿）Local skin swelling or suppuration（化脓） Local tissue destruction and necrosis（坏死） 12Pathogenesis Ocular sparganosis 45.6%blindness, exophthalmia眼球突出，

7、lagophthalmia兔眼症, ulceration of the cornea角膜溃疡. intense pain, irritation, excessive lacrimation流泪, and marked swelling of the eyelids. 眼裂头蚴病 Pathogenesis Subcutaneous sparganosis 31%itchy, inflamed and painful migratory nodules (come and go )Oral and Marxillofacial sparganosis 20.1%Pathogenesis Cere

8、bral sparganosis : 2.3%seizures, fatigue, confusion, headaches, memory loss, coma, fever, paresthesias感觉异常, hemiparesis偏瘫, most common：the cerebral hemispheres, especially the frontoparietal lobes额顶叶, a massive cerebral hemorrhageViscera sparganosis DiagnosisHistory Biopsy tissue Computed tomography

9、 (CT) Magnetic resonance imaging (MRI)Enzyme-linked immunosorbent assay (ELISA)Clinical propertiesDistributed predominately in Asia ,in China ：Guangdong, Guangxi and Fujian ProvincesTreatment Surgical removal of sparganum larvae Praziquantel ： limited success.Prevention and control Well cooking of m

10、eat Dont application with flesh of frogs or snakesNot drinking raw water Diphyllobotrium latum - the fish tape wormCommon in fish eating carnivores：human， dog，Adults ： quite long (10 m) with up to a million eggs per dayWater needed in egg-embryonationLife cycle ：similar to that of Spirometra mansoni

11、阔节裂头绦虫Mature plerocercoids can be easily seen as white massesParatenic hostAbout 9 million people infected (northern Europe , Japan, USraw fish dishesDiphyllobotrium latum - the fish tape wormHymenolepis膜壳绦虫属 two different types: H. nana (Dwarf tapeworm) H. diminuta (Rat tapeworm)Phylum: Platyhelmin

12、thesClass: CestodaOrder: Cyclophyllidea圆叶目Genus: Hymenolepis 膜壳属微小膜壳绦虫(Hymenolepis nana)Dwarf tapeworm. The smallest of all tapeworms found in humansNo intermediate host needed 1. Morphology Very small, 580 mmProglottids are wider than long, The genital pores are unilateral.Scolex : spherical, 4 suc

13、kers 20-30 hooksEgg Shell Embryonic membraneOncosphere oval or subspherical 40-60 um x 30-50 um 4 to 8 polar filamentsThe oncosphere has six hooks. Polar filaments Life cycleWorld wide distributed common in childrenIntermediate host not requiredCysticercoids develop in the lymphatics of villiHymenol

14、epis nana Intestinal auto-infectionLife cycle Definitive host : mouse and human， small intestineIntermediate host: flour beetle and grain beetleInfected when eats an infected intermediate host or egg.Internal autoinfection:自体内感染 the eggs release their oncospheres directly into the intestine without

15、passage through the external environment.Manifestations Symptoms most apparent in children.Gastrointestinal discomfortDiarrheaWeaknessPoor appetite/anorexiaHeadachesComplications: discomfort and dehydration脱水 from prolonged diarrheaDiagnosis Examination of the stool : eggs and parasites confirms the

16、 diagnosis. Concentration techniques and repeated examinations 缩小膜壳绦虫（Hymenolepis diminuta）H. diminuta is mainly a parasite of rats, occasionally in humanDifferentiation depends on microscopy of their eggs Epidemiology （comparison）In humans:Hymenolepis nana are much more common than Hymenolepis dimi

17、nuta. H. nana : the most common cause of all cestode infectionsIncidence : higher in children and institutionalized groups. H. diminuta :less frequent Prevention and controlHygiene Elimination of ratsKeep grains, cereals, and flour stored properlyPraziquatel as a single dose (25 mg/kg )is currently

18、the treatment of choice. SPECIESSTAGE FOUND IN HUMANSCOMMON NAMEPATHOLOGYTHERAPYDiphylobothrium latumAdultFish tapewormPernicious anemiaNiclosamidePraziquantelHymenolepis nanaAdultDwarf tapewormRarely symptomaticNiclosamidePraziquantelTaenia saginataAdultBeef tapewormRarely symptomaticPraziquantelTaenia soliumAdultLarvaePork tapewormRarely symptomaticBrain and tissue cystsNiclosamidePraziquantelAlbendazoleSurgeryEchinococcus granulosusLarvaeHydatid cyst diseaseSolitary tissue cystsSurgeryAlbendazoleEchinococcus multilocularisLarvaeAlveola