Authors

L van LieshoutC de Dood R van Grootveld J J de VriesL G VisserD SoonawalaP CorstjensG J van Dam ¹ Leiden University Medical Center, Netherlands

Discussion

Schistosomiasis in travellers and migrants is mostly diagnosed by detecting specific antibodies in serum. Although serology is sensitive and specific, it cannot distinguish active from past infection and it may take up to 10 weeks for seroconversion to occur. An alternative diagnostic tool is  detection of adult worm-derived circulating antigen in serum or urine. Here we explored the diagnostic value of an ultrasensitive robust lateral flow based test for the quantification of the Schistosoma Circulating Anodic Antigen (CAA)  utilising fluorescent up-converting phosphor reporter particles (UCP-LF CAA assay) within a non-endemic routine diagnostic laboratory setting. Serum samples from 78 serology positive cases were tested, including 36 travellers of which 14 had proven seroconversion. CAA was detected in 76% of the migrants and 56% of the travellers and was seen as early as four weeks after exposure. In three out of four subjects CAA was positive before antibodies were observed. All who were positive for microscopy and/or PCR in stool or urine had CAA in serum. After treatment, CAA  levels declined rapidly and all 19 controls were CAA negative. This explorative retrospective study indicates the UCP-LF CAA assay to be a highly accurate test for diagnosing schistosomiasis in a non-endemic setting.