Spirometra

• Spirometra spp.

  Cestodes in the genus Spirometra, including S. mansoni, S. ranarum, S. mansonoides and S. erinacei, as well as the aberrant Sparganum proliferum
• Life cycle of Spirometra spp.

  1. Definitive hosts (cats and dogs) pass unembryonated eggs in feces

  2. Eggs embryonate in water and release coracidia

  3. Coracidia ingested by crustaceans (first intermediate host)

  4. Procercoid larvae develop in crustaceans

  5. Crustaceans eaten by fish (second intermediate host), procercoid larvae transform into plerocercoid larvae

  6. Predator eats second intermediate host, plerocercoid larvae develop into adult in intestine of definitive host

  7. Humans are paratenic hosts (ingest plerocercoid larvae) or secondary intermediate hosts (ingest procercoid larvae)

  
• Pathology


  • Spargana may locate anywhere, including subcutaneous tissue, breast, orbit, urinary tract, pleural cavity, lungs, abdominal viscera and the central nervous system
  • Migration in subcutaneous tissues is usually painless, but when spargana settle in the brain or spine, a variety of neurological symptoms (weakness, headache, seizures, abnormal skin sensations)
• Pathology

  • Image of plerocercoid larva removed from chest of patient, about 70 mm long
• Spirometra eggs

  Operculated and immature, similar to those of Diphyllobothrium, although smaller
• Spirometra proglottids

  • Have a spiral uterus in contrast to the rosette uterus observed in Diphyllobothrium sp.
• Reported cases in the Philippines

  • 1935 - sparganum recovered from abdominal wall of seminarian from Pulilan, Bulacan
  • 1950 - fisherman from Libon, Albay with 4 cm chest lump
  • 1953 - 50 y.o. nun from Pulilan, Bulacan (missionary in Mindanao) with erythematous, slightly painful, pruritic mass in inner thigh
  • 1962 - 46 y.o. female with slightly painful, subcutaneous nodule at base of neck
  • Late 70's and early 80's - Human sparganosis reported as typical solid body with worm-like appearance
• Possible transmission

  • Drinking water with cyclops containing procercoid
  • Ingestion of second intermediate host with plerocercoid larvae
• Diagnosis

  • Finding of white larvae in the lesion
  • Computed tomography (CT) scan - an area of low density distinct from other brain lesions
  • Multi-dot ELISA - positive with Spirometra antigen (more specific)
• Prevention

  • Drinking filtered or boiled water
  • Cooking the intermediate hosts thoroughly
  • Avoid applying flesh of frogs to inflammed areas (as poultice)