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Schistosoma

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Summary

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Key Points

  • Schistosoma spp.
    • Characteristics
      • Types of trematode (fluke) parasites
    • Transmission
      • Exposure to infected freshwater via snails
        • Larvae penetrate skin of humans in contact with contaminated fresh water (e.g. swimming or bathing)
        • Human feces (mansoni, japonicum) and urine (haematobium) in water cause snail infection
    • Presentation: Schistosomiasis
      • Acute
        • Swimmer’s itch
          • Itchy rash at site of larval entry
        • Katayama fever (acute schistosomiasis syndrome)
          • Serum sickness-like disease
          • Sudden onset fever, urticaria, angioedema
      • Chronic
        • S mansoni
          • Egg has lateral spine
          • Endemic to Africa and South America
          • Lives in mesenteric vessels of intestine
            • Hepatomegaly
            • Diarrhea
        • S haematobium
          • Egg has terminal spine
          • Endemic to Africa and Middle East
          • Lives in urinary bladder venous plexus
          • Painless hematuria
            • Provokes chronic inflammation
            • Can lead to bladder cancer
        • S japonicum
          • Egg has vestigial (faint) lateral spine
          • Endemic to East Asia
          • Lives in mesenteric vessels of intestine
            • Hepatomegaly
            • Diarrhea
        • All strains
          • Pulmonary hypertension
    • Diagnosis
      • Eggs seen in stool (S. mansoni, S. japonicum) or urine (S. haematobium)
    • Treatment
      • Praziquantel
      • Corticosteroids for acute schistosomiasis