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Cestodes

Cestodes. Gregory L. Brower, D.V.M., Ph.D. Cell Biology and Anatomy School of Medicine Columbia, South Carolina. Cestodes (Tape Worms). Taenia solium (pork tapeworm) - Cysticercus Taenia saginata (beef tapeworm) Diphyllobothrium latum (fish tapeworm)

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Cestodes

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  1. Cestodes Gregory L. Brower, D.V.M., Ph.D. Cell Biology and Anatomy School of Medicine Columbia, South Carolina

  2. Cestodes (Tape Worms) • Taeniasolium(pork tapeworm) - Cysticercus • Taeniasaginata(beef tapeworm) • Diphyllobothriumlatum (fish tapeworm) • Echinococcusgranulosus (unilocularhydatid) • Echinococcusmultilocularis (alveolar hydatid) • Hymenolepis nana (dwarf tapeworm) • Hymenolepisdiminutia • Dipylidiumcaninum

  3. General Structure of Tapeworm • Head region (scolex) : contains suckers and hooks used to attach to a host organism. • Proglottids : square body segments used for reproduction.

  4. Tapeworm Structure • Scolex - Attachment organ • Zone of Proliferation - Undifferentiated area behind the scolex (neck region) • Strobilia - Chain of segments (proglottids) • Immature proglottids - developing reproductive • Mature proglottids: mature reproductive organs. • Gravid proglottids: contain eggs in the uterus.

  5. Immature Segment note that the reproductive organs are just beginning to differentiate. • (Carmine stained) Developing reproductive organs

  6. Mature Segments (Proglottids) Tapeworms are Hermaphroditic

  7. Taeniasis:Geographic Distribution • Worldwide, depending on dietary habits, and quality of cattle and pork farming.

  8. Taenia saginata and T. solium:Scolex And Proglottids

  9. Taenia solium (Pork Tapeworm)Morphology Adult Worm: 2-4 m long, 700-1000 segments: Scolex Neck Immature segment Mature segment Gravid segment

  10. Cystcercuscellulosae in Muscles of Pigs

  11. Cysticercus cellulosae It is soybean-like in shape, with the small scolex invaginated into the translucent cyst (left). The scolex evaginated from the cyst (right). Cysticercius cellulosae

  12. Taenia eggs The eggs of Taenia saginata and T. Solium are morphologically indistinguishable.

  13. Taeniasis:Life Cycle

  14. Taeniasis:Life Cycle

  15. Life Cycle

  16. Abdominal discomfort, epigastric pain, vomiting Physical presence of the worm Gastro-intestinal Site Symptoms Pathogenesis Other organs (cysticercosis) Cyst formation in brain, eye, lung and liver may cause related symptoms Physical mass and inflammation Taeniasis:Symptoms

  17. Cysticercosis

  18. Taeniasis:Diagnosis Symptoms History of eating undercooked beef or pork Recovery of proglottids and/or eggs in the stool

  19. Cysticercosis:Diagnosis • CNS and/or symptoms involving other organs • History of ingesting food with T.soliumeggs • Radiographic localization of cysticercal lesions in tissues

  20. Cysticercosis:Disease Cerebral cysticercosis

  21. Cysticercosis:Disease Cardiac cysticercosis Ocular cysticercosis

  22. Taeniasis:Treatment and Prevention Treatment • Praziquantel; scolex expulsion is essential Prevention • Adequate cooking of meat • Freezing meat below 10º C

  23. Fish TapewormDiphyllobothriumlatum Distributed worldwide: freshwater (great lakes)

  24. 1 cm Diphyllobothrium latum: Morphology

  25. Diphyllobothrium latum: Life Cycle

  26. Diphyllobothriasis:Symptoms Site Symptoms Pathogenesis gastro-intestinal abdominal discomfort, rarely severe cramping pain, diarrhea alternated by constipation, vomiting related to worm burden weight loss, vitamin B-12 deficiency physical mass and inflammation general

  27. Diphyllobothriasis:Diagnosis • symptoms • history of eating raw fish • recovery of proglottids and/or eggs in the stool

  28. Diphyllobothriasis:Treatment • Praziquantel is the drug of choice • Avoid uncooked fish from infested waters • Freezing for 24 hours and pickling kills the tape

  29. Hymenolepis nana (Dwarf Tape Worm)Morphology

  30. Hymenolepis nana (Dwarf Worm)Life Cycle

  31. Hymenolepis nana (Dwarf Worm)Symptoms • Lighter infections: mild abdominal disturbance • Heavier infections: enteritis

  32. Hymenolepis nana (Dwarf Worm)Diagnosis, Treatment And Control Diagnosis rodent infestation ova in the feces Treatment and Control Praziquantel is the drug of choice rodent population control

  33. Echinococcusgranulosus(hydatid)Geographic Distribution

  34. Echinococcusgranulosus(hydatid)Case History • 32-year-old Kenyan woman presented in Boston with a 3-month history of cough that was initially productive of thick, gray sputum that had gradually become blood-tinged. She had low-grade fevers. Chest radiography revealed an apparent elevation of the right hemidiaphragm. CT scan the chest with contrast medium revealed a low-density cystic mass measuring 13 by 13 by 10 cm in the right lower hemithora.

  35. Echinococcusgranulosus(hydatid)Case History • Ultrasound-guided aspiration of the contents of the cyst yielded clear, colorless fluid containing a protoscolex of Echinococcusgranulosus. Three days later, cystectomy was performed, with the use of specific precautions to prevent local spread of disease. After adequate antiparasitic treatment, follow-up radiography demonstrated reexpansion of the right lung. The patient has returned to her normal level of activity, and there is no evidence of recurrent disease.

  36. Echinococcus granulosus (hydatid)Morphology

  37. Echinococcus granulosus:Life Cycle

  38. Echinococcus granulosus:Life Cycle http://workforce.cup.edu/buckelew/

  39. abdominal distension, ascitis progressively growing cyst abdomen Site Symptoms Pathogenesis growing cyst liver obstructive jaundice pulmonary abscess, cough, chest pain growing cyst lung Jacksonian epilepsy growing cyst CNS Type-I hypersensitivity Fever, pruritus, urticaria, anaphylactoid reactions Echinococcus granulosus:Symptoms

  40. Echinococcus granulosus:Diagnosis • Endemicity • Symptoms • X-ray and CT scan • Serology • Skin (Casoni) test

  41. Echinococcusgranulosus: Treatment and Control • Surgical removal of the cyst • Praziquantel • Avoidance or treatment of infected canine

  42. Echinococcusmultilocularis(hydatid)Geographic Distribution

  43. Echinococcus multilocularis • Similar to E. granulosus, except: • Secondary hosts and reservoir are rodents. • The egg produces multilocular cysts. • The cestode is more resistant to chemotherapy.

  44. Echinococcusmultilocularis: Treatment and Control • Surgical removal of the cyst • Resistant to praziquantel; Albendazole has some effect • Avoidance control of rodent population

  45. Hydatid Cysts

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