An outbreak of schistosomiasis in travellers returning from endemic areas: the importance of rigorous tracing in peer groups exposed to risk of infection.

BACKGROUND: Each year, schools across Scotland send their students on exchange programmes to Malawi. Between 2005 and 2009, 22.8% of Scotland's new cases of schistosomiasis were from freshwater exposure in Malawi, with 41.5% diagnosed in 15-24 year olds. In January 2011, a 17-year-old male presented to our urology department with visible haematuria following freshwater exposure during a school trip to Malawi. He was subsequently diagnosed with urinary schistosomiasis.
METHODS: The potential involvement of other individuals from the trip prompted further public health enquiry. The school, public health department and education authorities were notified promptly and all individuals potentially exposed to Schistosoma haematobium were invited for screening.
RESULTS: All 21 participants of the exchange programme underwent serological screening. Thirteen tested positive for Schistosoma infection. Only two individuals displayed symptoms of schistosomiasis; the other 11 were asymptomatic.
CONCLUSIONS: Infection rates, even following a limited exposure to S. haematobium, are high. The majority of seropositive cases may never have symptoms. Therefore, a history of foreign travel to endemic schistosomiasis areas should be sought from any young person presenting with visible heamaturia and appropriate tests instigated. Schools should adopt policies forbidding activities involving freshwater exposure in Malawi. Effective public health measures must be set in place to trace and treat any other possible cases of exposure.