IMMUNODIAGNOSIS OF SCHISTOSOMIASIS-MANSONI IN A LOW ENDEMIC AREA IN SURINAM BY DETERMINATION OF THE CIRCULATING ANTIGENS CAA AND CCA

We evaluated the applicability of circulating antigen detection in ser um and urine for the diagnosis of Schistosoma infections in a low ende mic area. In total 389 individuals from Saramacca (Surinam) participat ed in the survey. Stool samples were examined using the Kato method, w hile circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were determined by highly specific monoclonal antibody-based EL ISA's. Also schistosome specific IgM antibodies were measured by the i ndirect immunofluorescence assay, but the diagnostic performance of th is test was found to be poor in this population. S. mansoni eggs were found in 29% of the examined cases, while CAA and CCA could be demonst rated in 23% and 17% of the serum samples and in 3% and 28% of the uri ne samples, respectively. Forty three percent of the study population was positive in at least one of these diagnostic assays, indicating th at each individual test misses a substantial part of the subjects with an active infection. In most positive cases, intensities of infection were very low. As 204 individuals participated in all screening assay s, diagnostic performance of each test was evaluated in this sub-popul ation. The highest sensitivities were achieved with the urine-CCA assa y and the parasitological examination, detecting 59 and 58 out of the 107 cases with an active infection, respectively. The serum-CAA assay detected 47 positive cases. Our results demonstrate that determination of circulating antigens, especially CCA in urine and CAA in serum, pr ovides information additional to the parasitological examination, for the assessment of prevalence and intensity of Schistosoma infection in low endemic areas.