Comparative assessment of the SjSAP4-incorporated gold immunochromatographic assay for the diagnosis of human schistosomiasis japonica

• Published in: Frontiers in public health 2023-09, Vol.11, p.1249637-1249637
• Main Authors: Mu, Yi, Rivera, Jonas, McManus, Donald P., Weerakoon, Kosala G., Ross, Allen G., Olveda, Remigio M., Gordon, Catherine A., You, Hong, Jones, Malcolm K., Cai, Pengfei
• Format: Article
• Language: English
• Subjects: diagnosis; droplet digital PCR; gold immunochromatographic assay (GICA); POC-CCA; Public Health; Schistosoma japonicum; schistosomiasis
• ISSN: 2296-2565; 2296-2565
• DOI: 10.3389/fpubh.2023.1249637

BackgroundSchistosomiasis, a disease caused by parasites of the genus Schistosoma, remains a global public health threat. This study aimed to validate the diagnostic performance of a recently developed gold immunochromatographic assay (GICA) for the detection of S. japonicum infection in a rural endemic area of the Philippines. MethodsHuman clinical samples were collected from 412 subjects living in Laoang and Palapag municipalities, Northern Samar, the Philippines. The presence of Schistosoma-specific antibodies in serum samples was tested with the SjSAP4-incorporated GICA strips and the results were converted to fully quantitative data by introducing an R value. The performance of the established GICA was further compared with other diagnostic tools, including the Kato-Katz (KK) technique, point-of-care circulating cathodic antigen (POC-CCA), droplet digital (dd) PCR, and enzyme-linked immunosorbent assays (ELISAs). ResultsThe developed GICA strip was able to detect KK positive individuals with a sensitivity of 83.3% and absolute specificity. When calibrated with the highly sensitive faecal ddPCR assay, the immunochromatographic assay displayed an accuracy of 60.7%. Globally, the GICA assay showed a high concordance with the SjSAP4-ELISA assay. The schistosomiasis positivity rate determined by the GICA test was similar to those obtained with the SjSAP4-ELISA assay and the ddPCR assay performed on serum samples (SR_ddPCR), and was 2.3 times higher than obtained with the KK method. ConclusionThe study further confirms that the developed GICA is a valuable diagnostic tool for detecting light S. japonicum infections and implies that this point-of-care assay is a viable solution for surveying endemic areas of low-intensity schistosomiasis and identifying high-priority endemic areas for targeted interventions.