A 19-year-old male university student of West Indian origin presented with 
fever, rigor, watery diarrhoea and noted intermittent generalised giant 
urticarial wheals of 2 weeks' duration. He swam in Lake Victoria, Uganda, 6 
weeks previously and developed a swimmers' itch. Ova of Schistosoma mansoni was 
demonstrated by the formol-ether concentration method of the faeces. An initial 
single dose (40 mg/kg) of praziquantel with prednisolone 40 mg once daily for 5 
days was given with no clinical deterioration of his condition. It is therefore 
safe and beneficial to give corticosteroid with chemotherapy in acute 
schistosomiasis (Katayama fever).