Schistosomiasis (=bilharzia) is an intravascular infection caused by the parasitic trematode worms schistosoma. It is carried by freshwater snails which release cercariae (=parasitic larvae). Human infection occurs after contact with water containing cercariae, for example after swimming.
Schistosomiasis is common in Asia/Africa/South America.
- Maculopapular rash – lasts up to 2 weeks
- “swimmer’s itch”
- Acute disease (=Katayama syndrome) – occurs 16 to 90 days after infection:
- RUQ pain
- Chronic disease (granuloma formation):
- Gastrointestinal inflammation, possibly causing haematochezia
- Liver fibrosis (S. mansoni, S. japonicum)
- Inflammation/obstruction of urinary tract with haematuria (S. haematobium)
- Increased risk of squamous cell carcinoma of bladder
- Acute transverse myelitis/subacute myeloradiculopathy (S mansoni and S haematobium)
- FBC – look for eosinophilia
- Microscopy of urine/stools
- Characteristic eggs – they have a lateral or terminal spine so look a little like a cartoon “speech bubble”
- Wait 2 months since last freshwater contact as it takes this length of time for eggs to become apparent
Treatment: oral praziquantel
Gray DJ, Ross AG, Li YS, McManus DP. Diagnosis and management of schistosomiasis.BMJ. 2011; 342: 2651.