Observations on some serological tests in schistosoma haematobium infections in man and experimental animals

This thesis is concerned with observations on the following serological tests: countercurrent immunoelectrophoresis (CIE), Enzyme-Linked Immunosorbent assay (ELISA) and the Thin Layer Immunoassay (TIA) in Schistosoma haematobium infections in man and experimental animals. CIE was found to be less sensitive and needing a higher concentration or antigens than the two other tests . ELISA proved to be very sensitive and specific for detecting antibodies in sera from patients with S . haematobium infections. There was strong cross reaction between S.mansoni antigens and sera from S.haematobium infections. Soluble egg antigen was more reactive than either adult worm antigen or cercarial antigen, and cercarial antigen gave a high percentage of false positives with sera from other helminth infections. The ELISA proved to be a promising test for serological monitoring or chemotherapy in hamsters, baboons and humans. A comparison was made of a new serological method, TIA and ELISA, in the detection and quantification of antibodies in schistosomiasis using adult worm antigen and sera from known S.haematobium and S.mansoni cases. TIA produced a small number of false positives with sera from other helminth infections whereas ELISA gave none . TIA has the advantage of being extremely simple to perform but has the disadvantage of requiring large amounts or antigen. It was possible to detect circulating schistosome antigen in the sera of infected baboons, and to some extent in humans, but not in hamsters using the ELISA test. Demonstration or the antigen-antibody complexes in the kidneys or infected hamsters, using the electron microscope and immunofluorescence was of limited success. Additional attempts were made to study the pathological changes in relation to serology at different times after treatment of groups of hamsters infected with S . haemutobium. The antibody levels declined in response to treatment . The inflammatory reactions progressively diminished but were still locally present at 20 weeks post treatment.