RESUMEN
With the aim to evaluate the circulating cathodic antigen (CCA) levels in relation to the different clinical phases of Schistosoma sp. infection a sandwich ELISA using monoclonal antibody 5H11 was performed. The sera of three groups of 25 Brazilian patients with acute, instestinal and hepatosplenic forms of S. mansoni infections were tested and compared to a non-infected control group. Patients and control groups were matched for age and sex and the number of eggs per gram of faeces was equally distributed among the three patient groups. Sensitivity of 100 per cent, 72 per cent, 52 per cent of the essays was observed for the intestinal, hepatosplenic and acute toxemic groups respectively. The specificity was 100 per cent. Intestinal and hepatosplenic groups presented CCA levels significantly higher in comparison to those observed for acute patients (F-ratio = 2,524; p = 0.000 and F-ratio = 6.314; p = 0.015 respectively). There was no significant difference of CCA serum levels between hepatosplenic and intestinal groups (F-ratio = 1,026; p = 0.316).