Tapeworm

• Taenia solium


  Pork tapeworm

  
• Phylum


  • Platyhelminthes
• Class


  • Cestoda
• Habitat


  Taenia solium, Taenia saginata
• Adult worm


  Live in human small intestine
• Larval stage


  Cysticercus cellulose, live in pig or human tissues causing cysticercosis
• Adult


  • Flattened ribbon-like, creamy white in color, measures about 2-4 m and has 700-1000 proglottides
• Scolex


  • Globular, 1mm, with 4 suckers, 1 rostellum and 25-50 hooklets arranged in a double crown
• Neck


  • Narrowest part of the body and budding zone containing germinative tissue
• Immature proglottides

  • Width > length
• Mature proglottides


  • Width = length, have 150-200 testes, a centrally straight uterus and 3 lobes of ovary
• Gravid proglottides


  • Width < length, contain a branched uterus filled with eggs, 7-13 main branches on each side of the uterus stem
• Tapeworms are hermaphroditic
• Egg


  Spherical, diameter 31 to 43 µm, with a thick radially striated brown embryophore, contains an oncosphere with 6 hooklets
• Cysticercus cellulose


  Semitransparent bladder, like a white pomegranate seed about 0.6-1cm, contains fluid and a white scolex with 4 suckers and hooklets
• Cysticercus cellulose


  1. Under stimulation of bile, the scolex invaginates in the bladder

  2. The scolex evaginates
• Life cycle


  • Final host: man
  • Intermediate host: pig (or man)
  • Infective stage: cysticercus and egg
  • Infective mode: eating raw bean-pork
  • Site of inhabitation: adult in small intestine; cysticercus in tissues
  • Infective mode of cysticercosis: endogenous, exogenous auto-infection and foreign source
  • Life span: more than 25 years; cysticercus can survive 5-6 years in human body
• Taeniasis


  Caused by the adult residing in small intestine of man
• Cysticercosis


  Caused by the cysticerci living in human tissues, manifestations vary with the number of cysticerci and the tissues and organs involved
• Subcutaneous type


  • Subcutaneous nodules usually found in head, limbs, neck, abdomen and back, painless
• Ocular type


  • Cysticercus in the tongue and the eye
• Brain type


  • Cysticercus in the brain
• Diagnosis of Taeniasis


  Confirmative diagnosis made by finding gravid proglottides or egg in stool
• Diagnosis of Cysticercosis


  Biopsy of subcutaneous nodules, X-ray, MR for brain type, ophthalmoscope examination for ocular form, immunological tests
• Taenia saginata


  Adult worms live in human small intestine causing Taeniasis, larval stage live in tissues, prevalent all over the world

  
• Taenia saginata life cycle


  Intermediate host is cattle, cysticercus bovis cannot live in human, other aspects same as T. solium
• Diagnosis of Taenia saginata


  Finding of gravid proglottids or eggs at the perianal region by cellophane tape method

  
• Differences between T. solium and T. saginata


  • Body length
  • Scolex
  • Mature proglottid
  • Gravid proglottid
  • Cysticercus