Schistosomiasis, or bilharzia, is a parasitic flatworm infection. The three main species of schistosome are S. mansoni, S. japonicum and S. haematobium.

Acute infections

Acute symptoms typically only develop in people who travel to endemic areas, as they don't have any immunity to the worms.

Acute manifestations may include:

• swimmers' itch
• acute schistosomiasis syndrome (Katayama fever)
  • fever
  • urticaria/angioedema
  • arthralgia/myalgia
  • cough
  • diarrhoea
  • eosinophilia

Chronic infections

Schistosoma haematobium

These worms deposit egg clusters (pseudopapillomas) in the bladder, causing inflammation. The calcification seen on x-ray is actually calcification of the egg clusters, not the bladder itself.

Depending on the site of these pseudopapillomas in the bladder, they can cause an obstructive uropathy and kidney damage.

This typically presents as a 'swimmer's itch' in patients who have recently returned from Africa. Schistosoma haematobium is a risk factor for squamous cell bladder cancer.

Features

• frequency
• haematuria
• bladder calcification

Investigation

• for asymptomatic patients serum schistosome antibodies are generally preferred
• for symptomatic patients the gold standard for diagnosis is urine or stool microscopy looking for eggs