Transcript Sruthi
helminths • Helimenths are worm like parasites and includes 2 phyla • Platyhelimenthes • Cestoda • trematoda • Nematihelimenthes • nematoda Cestodes are dorsiventrally compressed flat worms and so they are called tape worms cestoidea Pseudophlylid ea diphyllob otridiae Dyphyllob otrium D.latum Spirometra S.mansoni S.theileri Cyclophyllidea Hymenolepid ae Diphylidii ae Hymenol epis Diphylidiu m Taenia Echinococ cus H.Nana, H.diminuta , D.caninu m T.solium, T.saginata E.granulosua,E ,mulilocularis,E .vogeli Teniidiae GENRAL CHARECTERS OF CESTODA • segmented , dorsiventrally compressed • Varies from few cms to mts • Hermaphrodites, complete segments • Coelom, respiratory € circulatory systems absent • Excretory € nervous sys present…… Morphologic forms € morphology • Morphologic forms include • Adult worm: • Scolex • Neck • strobila • Egg: • Larva: • • • • Cysticercous Coeneures Procercoid Hydatid cyst • cysticercoid • coracidium • pleurocercoid Adult worm morphology • Scolex: it is a distended organ • Pseudophyllidiens consists a pair of longitudinal grooves called bothria • Cyclophylidiens consists of 4 suckers, occasionally rostellum is present……… • Neck:pseudophylidiens neck is thin un segmented longer than head. • Cyclophyllidiens , short fragile, 3-7mm • Strobila • 3 types of proglottids • Immature proglottid: • present near neck • Immature…. male and female sex organs • Mature proglottid: • Larger than prev.. Well differentiated sex organs • At times 2 sets • Male genital organs – dorsal, • Multiple testes • Vas efferentia • Vas deferens—genital atrium………. • Female genital 0rgans- ventral • Ovary bilobed • Oviduct • Spermatic duct • Ootype • Uterus • Gravid proglottid: • lies most distal • Uterus filled with fertilized ova Egg……. • Pseudophllidien • Ovoid • Operculated • Initially not embrionated • Ciliated embryo formed later • Cylophyllidien • Non operculated • 2 coverings 1. Inner embryophore 2. Thin shell membrane diphyllobothrium Pseudophyllidien tape worms diphyllobotrium(leaf like structures having 2 sucking org) • Identified by BONNET • life cycle by JANIKE € ROSEN • Common names: • fish tape worm , • dog tape worm • Epidemiology • 9 million people in world • Poor sanitation • Geographical dist • Not so common in India, 1st case 1998 Vellore • More prevalent in US, Canada, Europe, Japan • Habitat • Morphology • Small int of fish eating mammals, mostly man • Adult worm • 10 m, • 3000 proglotids , • ivory colored • Scolex: • Almond shaped • 2-3mm*1mm • 2 slit like grooves….. • Neck • Longer than head • Strobila • 3000 above proglotids 1. Immature 2. Mature 3. Gravid • Coiled rosette patterned uterus….. • More than a million eggs a day • Egg • • • • • • Yellowish brown 70*45µm Bile stained Embryonated Operculated Doesn’t float on Saturated salt solution • It is non infective to man •Larval stages •Coracidium • 1st stage larva • Develop in water •Procercoid • 2nd stage larva • Develop in copepods •Pleuricercoid • 3rd stage larva • Devolop in fresh water fish • Adult worm resides in small intestine • Lays operculated eggs • Faecus • Ciliated embryo—1-2wks • Damp soil for months Life cycle of diphyllobotrium • Has a single definitive host: any mammal which feeds on fresh water fish • Intermediate host • 1st intermediate host: small copepods , mainly Diaptomous, cyclops • Fresh water fish which feeds on copepods CLINICAL MANIFESTATIONS • Most of the infections r by a single worm, vague r no manifestations • Manifestations include 1. 2. 3. 4. fatigue € weakness Diarrhoea Numbness of extremities Wt loss • Abdominal discomfort • Fever Complications • Adult worm has high affinity for vit B-12 • Also interferes with combination of B-12 and intrinsic factor • Results in hyperchromic ,macrocytic, megaloblastic anemia……PERNICIOUS ANEMIA • Which manifests as • Dyspnoea • Glossitis • Fatigue • Tachycardia • Host immunity plays no role…………. • Good Prognosis……… • Reservoir, source, transmission • Man is opportunistic host & reservoir • Transmission orally ,eating under cooked fresh water fish • Eating raw liver of fish • sevile • Diagnosis….. • Patients with pernicious anemia, from endemic area, habit of eating raw fish, or history of eating under cooked fish • Lab diagnosis • • • • • Mostly parasitic Demonstration of egg, microscopically Direct wet mount preparation At times chains of proglottids passed along with stools Identified by the presence of rosette uterus •Treatment • PRAZIQUANTEL • NICLOSAMIDE • PRIZIQUANTEL • Orally, in single dose, 5mg-10mg/Kg Bodywt • Vit B-12 parenterally •Prevention & control • Thoroughly cooked fish, or freezing at -1o◦c for 24 hrs to 48hrs…… • Avoidance of eating raw & under cooked fish • Prevention of contamination of lake, river water or reservoir with human faeces • Control of copepods spirometra Introduction • Not a common human parasite • Medically imp species include • Spirometra mansoni • Spirometra theileri • Spirometra erinance • It is quite related to Diphyllobotrium • Man is an accidental host & acts as an intermediate host • Measures about 4cms-10cms in length • White in color • Habitat • Generally ,Subcutaneous tissue, orbit, muscles, lymph nodes, any part of the body………… • Hosts: • Definitive host : • dogs & cats • Intermediate host: • 1st intermediate host: copepods, body cavity , procercoid • 2nd intermediate host: fish frog snake, various organs , plerocercoid • TRANSMISSION • drinking infected water • Eating raw or poorly cooked amphibians • Using infected frog or snake flesh as poultice • Plerocercoid larva –spargana-sparganosis • Occurs , SE Asia, N&S America , Sparangnosis SPARANGNOSIS sparangnum 1. Procercoid larva liberation 2. Frog /snake tissue , Migration-subcutaneous tissue& other organs • Encysted in fibrous nodules,painfull-2cm dia, • Serious, when end up in brain, eye,lymphatic system • Diagnosis • Definite diagnosis is made only after surgical removal of nodule & demonstration of larva • Absence of suckers and hooklets differentiates 4m others……. • Species diagnosis is by feeding living cats with spargana and observing the adult • Prevention & control • Filtering water • Avoid consumption/contact with raw flesh, which might harbour plerocercoid larva • Treatment Rx • Surgery is the only treatment • Includes surgical removal of plerocercoid larva & nodule containing larva CYCLOPHLLIDIEN TAPE WORMS • • • • GENUS HYMENOLEPIS GENUS TAENIA GENUS ECHINOCOCCUS GENUS DIPYLIDIUM • General characters • These have 4 suckers, a rostellum at times with hooks • T. worms of medical importance belong to Taenioidea • Flattened body , • Simple suckers • Non operculated egg Family hymenolepididiae genus hymenolepis • • • • • Segments broader than long Testis 1-4….., Sac like unilateral uterus Causes hymenolepiasis in humans Of medical importance include • H. nana • H . diminuta HYMENOLEPIS NANA Dwarf tape worm • Single host • HABITAT • Ileal portion of small intestine , man, rat ,mouse • MORPHOLOGY • Small tread like, 10-40cms • Consists of • Scolex • Neck • Strobila(//200) • SCOLEX • Globular • 4 suckers, rostellum (retractable), 20-40 hooklets • NECK • Long ,posterior to head • STROBILA • 2O0 segments • O.3mm*0.9mm • Monoecious • 2wk lifespan……. • 1000-2000 AW in infected person • INFECTIVE FORM • Egg of the worm • EGG • • • • • • Colorless Oval 30µm-45µm in dia 2 membranes……….. Space Inner membrane 2 poles, polar filaments 4-8 Onchosphere-3 pairs of hooklets, Eggs released by disintegration of gravid • LIFE CYCLE • Completed in single host, no intermediate host, man , mouse, rat acts as both def & intermediate host. • 2 types of life cycles • Direct • Indirect • DIRECT CYCLE • Ingestion- eggs / proglottids of eggs • Small int lumen-oncosphere release- villus penetrationcysticercoid development.(4 days) • villus rupture– free cysticercoid attaches another villus……….. • > 2weeks- adult worm • Strobilization 30 days after infection….. Egg hatch in the intestine-auto infection • INDIRECT CYCLE • It is with grain flour eating beetles, fleas , moths • Ingestion of egg…….stimulation of onchosphere • Enters body cavity, transforms into CYSTICERCOID Larva • Accidental ingestion by man, develops into Adult worm • PATHOGENICITY& clinical manifestations……… • Tolerated even in large numbers • CL. Manifestations due to Allergic reaction include, pruritus of nose and anus • Anorexia , Abdominal pain. Diarrhoea, • Headache, dizziness , restlessness, convulsions • HOST IMMUNITY • Direct cycle –strong humoral & cellular immunity………. • Incapable of destroying , worms which already invaded the gut wall •prognosis is excellent even without treatment • • • • • • • EPIDEMIOLOGY&GEOGRAPIC DIST 36 million all over the world 4-10 yrs children Common in temperate than tropical Ubiquitous, SA, SE, lat amrca ME asia In India gujrt, AP, TN, chandigarh , haryna high incidence in WB RESERVIOR SOURCE TRANSMISSION… OF DISEASE • Man is main reservoir • Human feces main source • Transmission – faeco oral ingestion • Contamination of food & water • Rarely ingestion with fleas • LAB DIAGNOSIS • Egg demonstration in faeces by direct microscopy, salt flotation& formalin ether conc… methods. • eosinophillia • TREATMENT • PRAZIQUANTEL • NICLOSAMIDE • PROPHYLAXIS • Personal hygiene • Sanitary improvements • Un contaminated food & water • Rodent control