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helminths

helminths. CESTODA TREMATODA NEMATODA. 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. GENRAL CHARECTERS OF CESTODA.

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helminths

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  1. helminths CESTODA TREMATODA NEMATODA

  2. 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

  3. 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……

  4. Morphologic forms € morphology • Morphologic forms include • Adult worm: • Scolex • Neck • strobila • Egg: • Larva: • Cysticercous • cysticercoid • Coeneures • coracidium • Procercoid • pleurocercoid • Hydatid cyst

  5. 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

  6. 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

  7. Egg……. • Pseudophllidien • Ovoid • Operculated • Initially not embrionated • Ciliated embryo formed later • Cylophyllidien • Non operculated • 2 coverings • Inner embryophore • Thin shell membrane

  8. diphyllobothrium

  9. Pseudophyllidien tape wormsdiphyllobotrium(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

  10. 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

  11. Strobila • 3000 above proglotids • Immature • Mature • Gravid • Coiled rosette patterned uterus….. • More than a million eggs a day

  12. Egg • Yellowish brown • 70*45µm • Bile stained • Embryonated • Operculated • Doesn’t float on Saturated salt solution • It is non infective to man

  13. 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

  14. Adult worm resides in small intestine • Lays operculated eggs • Faecus • Ciliated embryo—1-2wks • Damp soil for months

  15. 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

  16. CLINICAL MANIFESTATIONS • Most of the infections r by a single worm, vague r no manifestations • Manifestations include 1. fatigue € weakness 2. Diarrhoea 3. Numbness of extremities 4. Wt loss

  17. Abdominal discomfort • Fever

  18. 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

  19. 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

  20. 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

  21. 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

  22. 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

  23. 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

  24. 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

  25. LIFE CYCLE OF SPIROMETRA… Spp

  26. 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

  27. 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

  28. Treatment Rx • Surgery is the only treatment • Includes surgical removal of plerocercoid larva & nodule containing larva

  29. 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

  30. Family hymenolepididiaegenus hymenolepis • Segments broader than long • Testis 1-4….., • Sac like unilateral uterus • Causes hymenolepiasis in humans • Of medical importance include • H. nana • H . diminuta

  31. 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)

  32. 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

  33. 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

  34. DIRECT CYCLE • Ingestion- eggs / proglottids of eggs • Small int lumen-oncosphere release- villus penetration- cysticercoid 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

  35. 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

  36. 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

  37. 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

  38. 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

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