Detection of schistosome circulating antigens CCA and CAA: diagnostic test interpretation and application

Abstract

Schistosomiasis is a parasitic infection caused by worms of the genus Schistosoma. It is a neglected tropical disease, affecting mainly populations living in poverty without adequate sanitation. Treatment relies on one drug mainly, praziquantel, and its efficacy is dependent on the diagnostic tool used.

Due to the parasite’s intravascular localisation, it is difficult to directly quantify them in infected humans. Thus, methods of detection like worm-derived circulating cathodic antigen (CCA) in urine or circulating anodic antigen (CAA) in urine and serum, have gained more attention. This thesis aims to explore and shed light on how to interpret schistosome-related circulating antigens CCA and CAA. We have addressed the interpretation of schistosome related assays in endemic and non-endemic regions, supported by data obtained from an animal study. Different diagnostic value can be attributed to different assays within different contexts. The results highlight the importance of a better understanding of antigen excretion patterns by different species to support optimalisation of antigen-based diagnostics of schistosomiasis.