Echinostoma ilocanum

• Common Name of E. ilocanum

  Garrison’s Fluke
• Disease Caused by E. ilocanum

  Echinostomiasis
• Habitat of E. ilocanum

  Small intestines (duodenum)
• Intermediate Host of E. ilocanum

  1st IH: Snails (Gyraulus convexiusculus, Vivipara angularis)

  2nd IH: Snails and clams (Pila luzonica, Bullastra cumingiana)
• Final Host of E. ilocanum

  • Principal: Humans, dogs, rats, snail-eating mammals
  • Reservoir: Dogs, rats
• Diagnostic Stage of E. ilocanum

  Unembryonated eggs in feces
• Infective Stage of E. ilocanum

  Metacercaria
• Mode of Transmission (MOT) of E. ilocanum

  Ingestion of infected intermediate host (snails)
• Treatment for E. ilocanum

  • Praziquantel (40 mg/kg, single dose)
• Egg Characteristics of E. ilocanum

  • Straw-colored
  • Ovoid
  • 83-116 µm by 58-69 µm
  • Operculated with posterior thickening
  • Small, dot-like operculum
  • Similar to Fasciola eggs
  • Also known as “germ ball egg”
• Adult Characteristics of E. ilocanum

  • Reddish-gray in color
  • 2.5-6.5 mm by 1-1.35 mm
  • Anterior end:
  • Tapered with a circumoral disc or collar spine attachment
  • 49-51 collar spines surrounding the disc
  • Oral sucker at the center of the oral disc
  • Ventral sucker: Located at the anterior fifth of the body
  • Posterior end: Tapered
  • Tegument: Covered with plaque-like scales
  • Testes: Bilobed, located posteriorly
  • Ovary: Ovoid, located in front of the testes
  • Intestinal ceca: Unbranched
• Additional Notes on E. ilocanum

  • First discovered among prisoners of Manila Bilibid Prison (1907)
  • Endemic in Ilocos province, Leyte, Samar, and Mindanao
  • Only trematode where both 1st and 2nd IHs are snails
• Life Cycle of E. ilocanum

  • Adults lay immature eggs, which are passed through feces
  • Eggs mature in water within 6-15 days
  • Miracidia penetrate 1st IH (snails)
  • Miracidia develop inside 1st IH (Sporo → Redia → Cercaria)
  • Cercariae encyst in 2nd IH (snails and clams)
  • Metacercariae ingested by final host
• Clinical Manifestations of E. ilocanum

  • Mild infections:
  • Inflammation and mild ulcerations (due to penetration of collar spines into intestinal mucosa)
  • Heavy infections:
  • Nausea
  • Vomiting
  • Diarrhea
  • Fever
  • Abdominal pain
• Laboratory Diagnosis of E. ilocanum

  Demonstration of operculated ova in feces

  • Unembryonated in feces
  • Careful measurement to differentiate from Fasciola eggs
  • DFS, FECT, Microscopy
• Prevention of E. ilocanum

  • Thorough cooking of snails in endemic areas
• Egg of E. ilocanum


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• Adult E. ilocanum


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