AUTHOR=Hoekstra Pytsje T. , de Dood Claudia J. , Abdoel Theresia , Hilt Stan , van Diepen Angela , Polman Katja , Kremsner Peter , van Lieshout Lisette , Kreidenweiss Andrea , Adegnika Ayola Akim , Fusco Daniela , Rasomoelina Tahinamandranto , Rakoto Andrianarivelo Mala , Rakotozandrindrainy Raphaël , Rakotoarivelo Rivo Andry , Sicuri Elisa , van Dam Govert J. , Corstjens Paul L. A. M. 

TITLE=Detecting two Schistosoma circulating antigens – CCA and CAA – in urine and serum to improve diagnosis of human schistosomiasis

JOURNAL=Frontiers in Parasitology

VOLUME=3

YEAR=2024

URL=https://www.frontiersin.org/journals/parasitology/articles/10.3389/fpara.2024.1460331

DOI=10.3389/fpara.2024.1460331

ISSN=2813-2424

ABSTRACT=<sec><title>Background</title><p>Schistosomiasis is caused by infection with parasitic <italic>Schistosoma</italic> worms and affects more than 250 million people globally. The detection of schistosome derived circulating cathodic and anodic antigens (CCA and CAA) has proven highly valuable for detecting active <italic>Schistosoma</italic> infections, causing both intestinal and urinary schistosomiasis.</p></sec><sec><title>Aim</title><p>The combined detection of CCA and CAA was explored to improve accuracy in detecting <italic>Schistosoma</italic> infections.</p></sec><sec><title>Methods</title><p>Parallel detection of CCA and CAA was performed on two banked sample sets with matching serum and urine samples from <italic>Schistosoma mansoni</italic> (<italic>Sm</italic>) and <italic>S. haematobium</italic> (<italic>Sh</italic>) infected individuals using the non-concentration based lateral flow (LF) test comprising the sensitive luminescent up-converting reporter particle (UCP) technology.</p></sec><sec><title>Results</title><p>Parallel detection of CCA and CAA increased the positivity rate for detecting both <italic>Sm</italic> and <italic>Sh</italic> infections compared to the detection of either antigen separately, demonstrating the added value of detecting both antigens in a single sample to confirm diagnosis, independent from the <italic>Schistosoma</italic> species. Significantly higher CCA concentrations in urine were observed in <italic>Sm</italic> infected individuals compared to <italic>Sh</italic> infected individuals, while serum CCA-concentrations were similar between species. CAA concentrations were higher in serum compared to those in urine, irrespective of species. When exploring the relationship of CCA and CAA in urine, the CCA/CAA ratio in <italic>Sm</italic> infected individuals was significantly higher than in <italic>Sh</italic> infected individuals, while no differences were observed in serum.</p></sec><sec><title>Discussion and conclusion</title><p>Parallel detection of CCA and CAA via the UCP-LF platform showed added diagnostic value through an increased positivity rate for the detection of <italic>Sm</italic> and <italic>Sh</italic> infections, compared to only detecting either of the antigens. The combined and quantitative detection of CCA and CAA is indicative for identifying the infecting species, but needs further exploration.</p></sec>