SCHISTOSOMIASIS (bilharziasis)

Disease of the large intestine and the urinary tract due to infestation by a Schistosoma blood fluke.

Causes

  • The larvae form (cercariae) of Schistosoma penetrate the skin from contaminated water and they migrate to different parts of the body, usually the urinary tract (Schistosoma haematobium) and the gut (S. mansoni)

Clinical features

S. haematobium (urinary tract)

  • Painless blood stained urine at the end of urination terminal haematuria
  • Frequent and painful micturition
  • In females: low abdominal pain and abnormal vaginal discharge
  • Late complications: fibrosis of bladder and ureters with increased UTI risks, hydronephrosis, infertility

S. mansoni (gastrointestinal tract)

  • Abdominal pain, frequent stool with blood-stained mucus, hepatomegaly
  • Chronic cases: hepatic fibrosis with cirrhosis and portal hypertension, haematemesis/melena are frequent

Differential diagnosis

  • Cancer of the bladder (S. haematobium)
  • Dysentery (S. mansoni)

Investigations

  • History of staying in an endemic area (exposure to water bodies)
  • Urine examination (for S. haematobium ova)
  • Stool examination (for S. mansoni ova)
  • Rectal snip (for S. mansoni)

Management

  • Praziquantel 40 mg/kg single dose
  • Refer patient if they develop obstruction or bleeding

Prevention

  • Avoid urinating or defecating in or near water
  • Avoid washing or stepping in contaminated water
  • Effective treatment of cases
  • Clear bushes around landing sites