An indirect haemagglutination reaction for the demonstration of Schistosoma mansoni circulating anodic antigen.

Using the IgG fraction of a monospecific sheep antiserum against the circulating anodic antigen (CAA) of Schistosoma mansoni, an indirect haemagglutination reaction for the determination of this antigen was developed. This is the first time that an IHA has been applied to the detection of circulating antigens in parasite infections. The IHA proved to be highly sensitive; CAA levels up to 20 ng/ml could be measured. At the moment it appears to be the most sensitive technique for the determination of CAA levels. CAA could readily be detected in the sera of S. mansoni infected hamsters and in the immune complexes isolated from these sera, but never in sera from human schistosome infections.