Accuracy of a new rapid diagnostic test for urinary antigen detection and assessment of drug treatment in opisthorchiasis

Abstract

Abstract Background Screening for opisthorchiasis, a parasitic worm infection affecting many millions of people in Southeast Asia, has traditionally relied on fecal egg examination using the formalin-ethyl acetate concentration technique (FECT). Although urinary ELISA has been used more recently, we developed a urinary antigen-based rapid diagnostic test (RDT) to simplify diagnosis and as a point-of-care test and field applications for surveillance and control of opisthorchiasis. Method A urinary Opisthorchis viverrini (OV)-RDT was developed using immunochromatographic methodology with a specific monoclonal antibody against OV. The diagnostic performance of the urinary OV-RDT was compared to that of fecal FECT and urinary ELISA. Cross-relativities of urinary OV-RDT with other helminthiasis coexisted with O.viverrini were determined. A field trial in application of OV-RDT was compared with urinary ELISA at baseline screening and assessment of drug treatment outcomes in opisthorchiasis. Results Urinary OV-RDT had sensitivity of 94.2% and specificity of 93.2%, compared to faecal FECT (n = 493). OV-RDT had high diagnostic agreement and quantitative correlation with urine ELISA and faecal FECT. Cross-reactions of OV-RDT with other helminthiases were few (2% n = 96). Field trials of OV-RDT (n = 1629) yielded comparable prevalence of O. viverrini between urinary OV-RDT and urinary ELISA. OV screening showed high diagnostic agreement (kappa > 0.8) between OV-RDT and urinary ELISA. The cure rates of opisthorchiasis at 1 month post-praziquantel treatment determined by OV-RDT (86.6%) and urinary ELISA (80.5%) were similar. Conclusions The OV-RDT test has high potential as a new tool for screening and evaluating treatment outcomes in opisthorchiasis. The ease of sample collection and simplicity of OV-RDT may facilitate mass screening, control and elimination of opisthorchiasis, thereby contributing to a reduction in the disease burden in Southeast Asia.