Collaborative study on antigens for immunodiagnosis of Schistosoma japonicum infection

Six research laboratories in Australia, Japan, the Philippines and the USA participated in a collaborative evaluation of immunodiagnostic tests for Schistosoma japonicum infections. The serum bank consisted of 385 well-documented sera from Brazil, Kenya, Philippines, Republic of Korea and Europe. Twelve S. japonicum antigen/test system combinations were evaluated.Crude S. japonicum egg antigens showed the highest sensitivity and specificity. The defined or characterized antigens showed no advantage over the crude antigens. Quantitative seroreactivity of all S. japonicum antigens showed a positive correlation with faecal egg counts (log x + 1) in all age groups. The performance of the circumoval precipitin test was satisfactory within the same laboratory but with differences in the results between laboratories. A monoclonal antibody used in a competitive radioimmunoassay test system performed as well as the crude egg antigens.The high sensitivity of crude S. japonicum antigens now permits further evaluation for wide-scale use in public health laboratories of endemic areas to support control efforts.