Parasitology lecture: Section 5 Cestodes

  1. Other name for Cestodes
  2. Tapeworm adults live where
    In vertebrates
  3. Where do larval tapeworms live
    Either vertebrae or invertebrate intermediate host
  4. Taenia pisiformis lives in which species?
  5. Cysticercus pisiformis lives in which species?
  6. All cestodes are what 2 things?
    • Indirect life cycle
    • Hermaphrodites
  7. Zoonotic causes of cestodes causing diplidiasis
    • Taenia multiceps
    • Taenia serialis
    • Taenia crassiceps
    • Echinococcus granulosus
    • Echinococcus multiocularis
    • Dipylidium caninum
  8. 2 forms of Echinococcosis in humans
    • Echinococcus granulosus (treatment/surgery)
    • Echinococcus multilocularis (Surgery)
  9. Disease Echinococcus granulosus causes in humans
    Cystic hydatid disease
  10. Echinococcus granulosus nickname
    Hydatid cyst tapeworm
  11. Aquatic tapeworms taxonomy
    • Phylum: Platyhelminths
    • Class: Cestoda
    • Order: Pseudophyllidea (Pesudotapeworms)
    • Cyclophyllidae ( true tapeworms)
    • Family: Eucestoda (land tapes)
    • Diphyllobothridae (water)
    • Genus: Diphyllobothrium and Spirometra
  12. What do aquatic tapes use mostly for intermediate hosts?
  13. At the apex of scolex dome shaped projection known as what?
  14. Storbila
    • Taenia one on margin
    • Mesocestoides one in center
    • Dipylidium two, one on each margin
  15. Diphyllobothridae facts
    • Aquatic tapeworm
    • One uterine pore
    • Discharge egg in intestines
    • Terminal segments become senile and detached in ribbons
  16. External to protect egg
    Egg capsule
  17. Serves as waste disposal area and port for nutrition and protection
  18. Vermiform embryo cestodes
  19. Term for cestodes that parasitize in any stage
  20. Purpose of intermediate host with cestodes?
    To develop scolex
  21. Treatment for cestodes
    • Praziquantel (Droncit) Bayer
    • Epsiprantel (Cestex)
  22. Most common tapeworm
    Dipylidium caninum
  23. Intermediate host for Dipylidium caninum
    • Ctenocephalides sp. (fleas)
    • Trichodectes canis (biting lice)
    • Linognathus setosus (sucking lice)
  24. Dipylidium caninum larval form name
  25. Mesocestoides larval name
    Tetrathyridium larvae
  26. Dipylidium caninum taxonomy
    • Phylum: Platyhelminths
    • Class: Cestoda
    • Order: Cyclophyllidea
    • Family: Dilepididae
  27. Life cycle of Dipylidium caninum
    • Oncospheres emerge from proglottids once passed in feces
    • Eggs ingested by fleas or lice, hatch and migrate to body cavity
    • Develops into cysticercoid stage with maturation of scolex in 1-2 days
    • Flea/lice ingested by dog, molts in intestines
    • Mature tape develops in 2-3 weeks and lay eggs
  28. Life cycle of Taenia
    • Eggs laid in soil and consumed by intermediate host
    • Hatches and attaches hexacanth embyros (S1) and moves to organs to develop scolices 
    • In organs embryo differentiates to S2
    • Definitive host eats the intermediate host 
    • Scolices attach to intestinal wall and mature
  29. Taenia pisiformis
    • Definitive host: Dog
    • Intermediate host: Rabbits or rodents
  30. Taenia taeniaformis
    • Definitive host: Cat
    • Intermediate host: Rodent
  31. Cysticercus fasciolaris facts
    Causes a lot of liver damage and may cause death of rodent before cat has a chance to consume
  32. Taenia hydatigena
    • "Thin necked bladder worm"
    • Definitive host: Dog
    • Found in intestines of wild dogs
    • Intermediate host: Sheep, cattle, swine
  33. Echinococcus granulosus definitive host and intermediate host
    • Definitive host: Dog/wolves
    • Intermediate host: Man, sheep, cattle, moose
  34. Echinococcus granulosus life cycle
    • Eggs are ingested, go to circulation and lodge in the liver and lungs
    • Develop into metacestodes with multiple scolices and are called hydatid cysts
    • Dog consumes intermediate host 
    • Man can get from kissing/handling dog
  35. Echinococcus multiocularis disease in man
    Alveolar Hydatid
  36. Echinococcus multiocularis intermediate host and definitive host
    • Definitive host: Dog and cat
    • Intermediate host: Rodents
  37. How often do animals test positive for tapes?
    • Fecal tests: 2.5% in routine exams
    • Necropsy: 35-62% when abdomen opened
  38. Cestodes in equine
    • Anoplocephala perfoliata 
    • A. magna
    • A. mammaliana 
    • Lives in intestines
    • Intermediate host: Mites
  39. Cestodes of ruminants
    • Moniezia expansa
    • M. benedeni
    • Intermediate host: Mite
    • Symptoms: Emaciation, abdominal and thoracic congestion, visceral enlargements 
    • Thysanosoma seen in sheep
  40. Cestodes of swine
    • Macracanthorhynchus hirudinaceus 
    • "Thorny headed worm"
    • Intermediate host: Any beetle
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Parasitology lecture: Section 5 Cestodes