Immunodiagnosis of Schistosomiasis haematobium and schistosomiasis mansoni in man. Application of crude extracts from adult worms and cercariae in the IHA and the ELISA.

The antibody responses of patients infected with S. haematobium or S. mansoni were investigated in an indirect hemagglutination test (IHA) and an enzyme linked immunosorbent assay (ELISA) using crude extracts of cercariae and adult worms of S. haematobium and S. mansoni, and of adult worms of S. japonicum. Patients were Africans from endemic areas, as well as Europeans who had acquired their infection relatively recently. Although the IHA showed a similar pattern of antibody responses as the ELISA it was less sensitive to assess recently acquired infections. Of special interest, antibodies found in patients with schistosomiasis mansoni cross-reacted strongly with antigens extracted from adult S. haematobium and S. japonicum. In contrast, sera of patients with schistosomiasis haematobium reacted significantly better with the homologous antigen than with heterologous antigens. In the ELISA the ratio of the absorption values of anticercarial antibodies to antiworm antibodies could be used to discriminate chronic from recent infections.