Serological diagnosis of Schistosoma japonicum infections in China.

This paper reports the results of the dot enzyme-linked immunosorbent assay (dot-ELISA) for the serological diagnosis of 50 acute and 50 chronic Schistosoma japonicum-infected patients employing keyhole limpet haemocyanin (KLH) and soluble egg antigen (SEA) as the specific antigens. The sensitivity of both antigens for the detection of both forms of this infection was 100% and 90%, respectively, using a test serum dilution of 1:100. When the serum dilution was adjusted to 1:500, the sensitivity of the KLH dot-ELISA was 82% and 15%, respectively. Thus, the different manifestations of this disease can be easily distinguished. None of the 44 uninfected control sera gave a positive result with the KLH dot-ELISA, though 6 (14%) did so with the SEA dot-ELISA. Cross reactivity rates of 13% and 23% were observed for clonorchiasis (n = 30) and paragonimiasis (n = 22). Therefore, the overall diagnostic effectiveness of both the KLH dot-ELISA and SEA dot-ELISA for the detection of S. japonicum infection in endemic regions in China was 97% and 92%, respectively.