Detection with a monoclonal antibody of an antigen, characteristic of the genus Schistosoma, excreted in the urine.

: In the host, the antigen excreted by schistosomes in the circulating blood is concentrated in the urine. A mouse monoclonal antibody of the IgM class type lambda, directed against an epitope of the intestinal epithelium of the adult worm, is obtained. The antigen found in the urine of the host as well as the monoclonal antibody has been previously characterized. It is of a polysaccharidic nature, is thermostable and specific for the genus Schistosoma. The antigen is found at all stages of the life cycle and, particularly, in the egg where it is found in large amounts. Detection of the antigen is by means of inhibition of the passive haemagglutination test. There is a fundamental advantage in detecting the metabolic antigen excreted by schistosomes instead of looking for circulating antibodies. The antigen is directly released by the parasite itself, antibodies being, by contrast, produced by the host, indirectly therefore, and in a way that varies from one individual to the next. Collecting urine specimens is, for field workers, easier than obtaining blood from the inhabitants. The detection of the antigen in the urine is made a rather simple procedure since the antigen is concentrated by the kidney and free in urine, instead of remaining conjugated with antibodies like it is in the blood. When used in the Cameroon for the study of prevalence in two foci of schistosomiasis, intestinal (Nalassi Emana) and urinary (Barombi Kotto), the test detecting the antigen in urine gives good correlations with the parasitological examinations looking for eggs of S. mansoni and S. haematobium in feces and urine.