Schistosomiasis is increasingly encountered among travellers returning from the tropics and is known for its focal endemicity, associated with the presence of the snail intermediate host in fresh water. Because schistosomiasis in travellers is often atypical or asymptomatic due to the low intensity of infection, many infections likely go undiagnosed and will develop into chronic schistosomiasis. Conventional treatment of schistosomiasis in travellers with praziquantel 40mg/kg daily dose is known for its modest success rate. Diagnosis of schistosomiasis relies on egg detection, which has a poor sensitivity in low burden infections, or serology, which is inadequate to monitor cure. The department of parasitology of the Leiden University Medical Center has developed a novel diagnostic test based on the up-converting phosphor technology (UCP) to detect circulating anodic antigen (CAA). This test can be performed on serum and urine to detect low intensity schistosomiasis infections and confirm cure after praziquantel treatment. This study will assess the performance of UCP-CAA in travellers with high-risk water contact.

Inclusion Criteria:

1. Any self-reported high risk water contact, including wading, showering, surfing, walking along wet shore bare-footed or washing with water from a high-risk source, within 12 weeks prior to reporting to the outpatient department
2. Agreement to perform routine diagnostic procedures to diagnose schistosomiasis infection
3. Willing to provide a maximum of three additional blood samples in addition to routine diagnostic procedures
4. Able to provide informed consent

Exclusion Criteria:

1. Previous treatment for schistosomiasis
2. Known positive schistosomiasis serology
3. The use of immunosuppressive or immunomodulatory drugs at presentation that compromise the interpretation of schistosomiasis serology

Travellers with reported high-risk water contact <12 weeks before inclusion.