Helminth

Echinococcosis

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Echinococcosis, Echinococcus granulosis, Echinococcus, Hydatid Disease

  • See Also
  1. Alveolar Hydatid Disease
  2. Helminth
  3. Parasitic Infection
  • Epidemiology
  1. Endemic worldwide in sheep raising areas
    1. Mediterranean
    2. Prior Soviet Union block nations
    3. Australia
    4. South America
    5. Africa
  2. U.S. sources
    1. Immigrants to North America
    2. Western U.S. sheep farmers
    3. Southwestern Native Americans
    4. Native Inuits in Alaska and Canada (Caribou, wolves)
    5. Some cases along Mississippi
  • Etiology
  1. Echinococcus granulosis
  • Pathophysiology
  1. Infection with the tapeworm Echinococcus larvae
    1. Produces expanding cysts (grow at 1-5 cm per year)
  2. Sites of involvement
    1. Liver (most common)
    2. Lung (second most common)
    3. Kidney
    4. Muscle
    5. Spleen
    6. Brain
    7. Bone
  3. Transmission
    1. Definitive Host: Dogs and other carnivores
    2. Intermediate host: Human, Sheep, Cattle
    3. Infections in Human by ingestion of ova
  • Symptoms
  1. Asymptomatic in 60% of cases (for 10-20 years)
  2. Cough
  3. Abdominal mass
  4. Hemoptysis
  5. Chest Pain
  • Complications
  1. Cyst rupture
    1. Anaphylactic reaction
    2. Pyopneumothorax
    3. Mediastinal erosion
  • Labs
  1. Complete Blood Count
    1. Eosinophilia may be present
  2. Skin test
    1. Casoni's Antigen
  3. Echinococcus serologic titer
    1. Test Sensitivity: 50% of lung infections
    2. EITB has highest sensitivity and Specificity
  4. Fine needle aspiration of cyst
    1. Tapeworm parts and Eosinophilic granules
  • Radiology
  1. Abdominal Ultrasound or CT: Liver or Kidney Cysts
  2. Chest XRay: Lung cysts
    1. Size: 1-10 cm in diameter
    2. Lower lobes and right side more commonly involved
    3. Consider CT Chest or MRI Chest
  • Management
  1. Surgical excision of cysts
  2. Anti-Helminth agents (used concurrently with surgery)
    1. Albendazole (Albenza)
    2. Mebendazole (Vermox)
      1. Not available as of 2012
  • Prevention
  • Education program in endemic areas
  1. Carefully wash fruits and vegetables before ingestion
  2. Avoid water potentially contaminated by dog feces
  3. Hand Washing after soil exposure
  4. Treat dogs frequently with worming formulations
  5. Avoid feeding dogs the entrails of livestock
  • Prognosis
  1. Mortality as high as 4-5% in untreated patients
  • References
  1. Chrieki (2002) Am Fam Physician 66(5):817-20 [PubMed]