Evaluation of Crude and Recombinant Antigens of Schistosoma japonicum for the Detection of Schistosoma mekongi Human Infection

Abstract

Asian schistosomiasis caused by the blood fluke Schistosoma mekongi is endemic in northern Cambodia and Southern Lao People’s Democratic Republic. The disease is mainly diagnosed by stool microscopy. However, serodiagnosis such as enzyme-linked immunosorbent assay (ELISA) with soluble egg antigen (SEA), has been shown to have better sensitivity compared to the stool examination, especially in the settings with a low intensity of infection. To date, no recombinant antigen has been assessed using ELISA for the detection of S. mekongi infection, due to the lack of genome information for this schistosome species. Thus, the objective of this study is to evaluate several recombinant S. japonicum antigens that have been developed in our laboratory for the detection of S. mekongi infection. The crude antigen SjSEA and recombinant antigens Sj7TR, SjPCS, SjPRx-4, and SjChi-3 were evaluated in ELISA using serum samples positive for S. mekongi infection. The cross-reaction was checked using sera positive for Ophistorchis viverrini. ELISA results showed that S. japonicum SEA at low concentrations showed better diagnostic performance than the recombinant antigens tested using the archived serum samples from Cambodia. However, further optimization of the recombinant antigens should be conducted in future studies to improve their diagnostic performance for S. mekongi detection.

Current advances in serological and molecular diagnosis of Schistosoma mekongi infection

“…Although considered as the gold standard for schistosomiasis diagnosis, microscopy is laborious and suffers low sensitivity in areas where prevalence of the disease is low. Antibody-based serological assay for S. mekongi may, therefore, contribute to the surveillance efforts directed towards case identification and eventual disease elimination [ 2 , 38 ].…”

“…It has acceptable sensitivity as well as potential applicability in the diagnosis of early stages of infection where traditional stool microscopy may be less sensitive as it was shown in schistosomiasis japonicum. Due to the continuous decline in the prevalence and the worm burden of patients infected with S. mekongi , antibody detection test may become valuable in such setting with near-elimination level of the disease [ 2 , 39 , 65 ].…”

A Miniature Biomedical Sensor for Rapid Detection of Schistosoma japonicum Antibodies

“…The schistosome antigen system is complex, primarily because the infection in the definitive host involves multiple cycles [ 11 ]. Over the past four decades, numerous antigens have been investigated for their potential utilization in antibody detection systems for schistosomiasis.…”

“…Thus, early screening and diagnosis remain the optimal approach to address schistosome infections, especially in high-risk areas and vulnerable populations. The schistosome antigen system is complex, primarily because the infection in the definitive host involves multiple cycles [11]. Over the past four decades, numerous antigens have been investigated for their potential utilization in antibody detection systems for schistosomiasis.…”