Raillietina

• Raillietina garrisoni


  Common tapeworm of rats

  
• Raillietina garrisoni

  • First reported by Garisson to be present in adult Filipino in 1911
• Intermediate hosts

  • Flour beetle: Tribolium confusum
  • Development of egg to cysticercoid larvae
• Infective stage

  Cysticercoid larva

  
• Autoinfection: NO
• If egg is ingested, infection does NOT occur
• Adult Raillietina garrisoni

  • 60 cm long
  • Scolex: Minute, subglobular, with 4 acetabula, armed rostellum with two alternating circular rows of 90 – 140 hammer-shaped hooks, PLUS spines surrounding the rostellum
• Mature Proglottid


  • Bilobed ovary
  • 36 – 50 ovoid testes
  • Genital pore opens on the anterior lateral border
• Gravid Proglottid

  • 2 mm long
  • 200 – 400 eggs capsules
  • Apolytic, motile
  • White color, resembling grains of rice when passed out with feces
• Egg capsules

  • 1 – 4 spindle-shaped eggs per capsule
• Oncosphere

  • Enclosed in two thin membranes: Outer elongated membrane, Inner spherical membrane
• Life cycle of Raillietina spp

  1. Definitive host passes feces containing gravid proglottids with egg capsules

  2. Proglottids or egg capsules are ingested by intermediate hosts. Eggs hatch releasing oncospheres which matures into cysticercoid (infective stage for definitive and accidental host)

  3. Definitive host ingests infected intermediate host and the cycle continues

  4. Humans ingest intermediate host with cysticercoid larvae. The larvae matures into adults in the small intestine and becomes gravid, apolyses to release proglottids or egg capsules to the external environment through the feces, and the cycle continues

  
• Pathogenesis and Clinical Manifestations

  • Generally Asymptomatic
  • Patients are brought to the doct when proglottids are passed out with feces
• Diagnosis

  Recovery of proglottides or ova in the stool
• Treatment

  • Drug of choice: Praziquantel
  • Sometimes, strobila or complete tapeworms are expelled even without treatment
• Prevention and Control

  • Elimination of rodents from households
  • Proper storage of grain products
  • Sanitary waste disposal