Diphyllobothrium

• Diphyllobothrium latum

  Fish tapeworm, Broad tapeworm

  
• Life cycle of D. latum

  1. Human ingests raw or undercooked infected fish

  2. Humans serve as definitive hosts, eggs passed in feces, embryonation in water

  3. Coracidia eaten by copepods/crustaceans (1st intermediate host)

  4. Procercoid larvae in copepod/crustacean

  5. Procercoid larvae in small fish (2nd intermediate host)

  6. Plerocercoid larvae in predator fish

  7. Human ingests infected predator fish
• Ingestion of raw or uncooked infected fish leads to human infection
• Infective stage


  • Coracidium (1st IH)
  • Procercoid larva (2nd IH)
  • Plerocercoid (sparganum) larva (3rd IH)
• Intermediate hosts

  • Copepod (1st IH)
  • Fish (perch, trout, salmon, pike) (2nd IH)
• Definitive host

  • Human, mammals
• Ova

  • Oval, bile-stained, yellowish brown with moderate thick shell, operculum, knob-like thickening, 66 x 44 um, contains abundant granules and unsegmented ovum, inconspicuous operculum and small knob
• Hatching of ova

  As hatching becomes eminent, viscous cushion or operculum swells, creating pressure to flip open and release coracidium
• Scolex

  • Spatulate or spoon-shaped with two bothria or sucking grooves, no rostellum or hooklets, thin and unsegmented neck longer than head
• Mature proglottid

  • Longer width than length, contains one set of reproductive organs, testes located dorsolateral
• Gravid proglottid

  • Disintegrate only when segment has completed its reproductive function
• Pathology

  • nonspecific complaints to mechanical obstruction (instestine, billiary)
• Diphyllobothriasis

  • bothriocephalus anemia: competes with host for vit b12
  • causes megaloblastic anema: mrgaloblast ic, hyperchromic
• Human sparganosis

  • ingestion of copepods with procercoid
  • becomes sparganum (plerocercoid) in the body
  • result in ocular or cutaneous sparganosis depending on the location
• Diagnosis

  • Fecalysis for demonstration of egg
  • surgical removal for sparganosis
• Treatment

  • Drugs of choice – Niclosamide, Praziquantel
  • Praziquantel is most of the time the recommended drug
  • Sparganosis – removed through surgery
  • Ocular Sparganosis – injected with 40% ethyl alcohol