Schistosomiasis

Background

• Caused by parasitic trematodes of the species Schistosoma
• Reservoir is freshwater snails
• Endemic in areas of Africa and Southern Asia
• The Cercariae (the stage of trematode released by the snail) can infect by direct penetration through the skin
• Infects >200million people worldwide with 10% suffering severe consequences

Clinical Features

Acute

• Cutaneous rash/pruritus from cercariae penetration (immediate)
• Katayama fever
  • Fever, abdominal pain, fatigue, cough, diarrhea, eosinophilia
  • Lasts 4-8 weeks

Chronic (mostly a chronic condition)

• Second most common cause of esophageal varices worldwide
• Greatly elevated bladder cancer rates in endemic areas
• Can cause renal failure, liver failure, pulmonary hypertension, GI bleeds and rarely CNS symptoms
  • Mostly through fibrosis of affected organs
• Genitourinary schistosomiasis
  • Caused by sores in the genital tract
  • May persist even after treatment
  • Greatly increases risk of HIV infection

Differential Diagnosis

• UTI
• STD
• Intestinal parasites
• Traveler's diarrhea

Evaluation

Work-up

• ELISA
• PCR from stool or urine
• Stool and Urine for ova/parasites
  • biopsy may be needed for those who do not show ova/parasites in stool/urine
• CBC, Alk Phos, GGT, ALT/AST, Cr, Blood cultures
• Consider ultrasound for hepatosplenic (periportal fibrosis) or urinary disease (hydro)
• Echocardiography and CXR for pulmonary hypertension and/or cor pulmonale
• Consider CT or MRI for CNS disease or further workup of periportal fibrosis

Management

• Praziquantel 20mg/kg PO for two doses in 1 day
  • S.japnonicum requires 3 doses in 1 day

Disposition

• Generally may be discharged
• Admit if concern for CNS infection

See Also

• Parasitic infection