Collaborative study on detection of circulating antigens in schistosomiasis japonica.

A workshop for collaborative study on circulating Schistosoma japonicum antigen detection was held at the Hunan Institute of Parasitic Diseases, Yueyang, Hunan Province in May, 1993. Eight laboratories from schistosomiasis-endemic provinces (municipalities) were joined in this study. Scientists from these laboratories performed serological assays in blind using their own brought test systems that developed during recent years. The serum samples tested covered 100 non-endemic controls, 190 from patients with active schistosomiasis, 110 from cured cases of schistosome-infection, and 170 from individuals harbouring other parasitic infections or hepatitis. Results of the study revealed an assay specificity, in terms of false positive rate, of 2% in Series B versus 14-46% in the other 7 series. With regard to assay sensitivity, all test series showed 95-100% for acute cases. While for chronic cases, test series A and F demonstrated sensitivities at 73.3% and 72.7% respectively. Other series were all below 70%. Negative reversion rates for sera from cured cases within 1 year post-treatment were below 33.3%, those within 2 years were 60% for Series E, while below 50% for all others except the Series H which was excluded due to an extremely low sensitivity obtained. The low values of these test series for chemotherapy assessment may be attributed to the poor specificity of the detecting systems used and/or the sample donors being not totally cured. It is strongly indicated that all the 8 test systems involved in the present study should further be improved in sensitivity, specificity as well as in capacity for pre-and post-treatment evaluations.