Comparative study between enzyme-linked immunosorbent assay and circumoval precipitin test using schistosoma mansoni and haematobium eggs in diagnosis of schistosoma mansoni

ABSTRACT

Sera from male patients of different age groups with simple and complicated S. Mansoni infection were examined for the presence of antischistosomal antibodies using the circumoval precipitin test [COPT] and enzyme linked immunosorbent assay [ELISA] tests. Both viable S. Mansoni and S. haematobium eggs were used as antigens for COPT. In ELISA test S. mansoni soluble egg antigen [SmSEA] and S. haematobium SEA [ShSEA] were also used. The results showed that SmSEA gave higher sensitivity than ShSEA in the ELISA. COPT was more sensitive with viable S. Mansoni eggs than on using viable S. haematobium eggs. ELISA test was found to be significantly more sensitive than COPT. The O.D. readings in ELISA test were higher by using SmSEA than those by ShSEA. The specificity obtained was 100% in ELISA test and COPT using viable S. mansoni eggs, whereas COPT done by viable S. haematobium eggs was 90% specific. The sensitivity of ELISA [using SmSEA] and COPT using either of the two antigens was directly increased with the egg output. At the same time the sensitivity of ELISA increased with the development of complications while the COPT sensitivity decreased with the development of complications. Higher sensitivity was obtained with ELISA test using SmSEA with increase of age whereas COPT sensitivity decreased with increasing age. These results suggested that ELISA test using SmSEA was the best in diagnosis of mansoniasis