EFFICACY OF AN ENZYME-LINKED IMMUNOSORBENT ESSAY IN THE DIAGNOSIS OF AND SEROLOGIC DISTINCTION BETWEEN ACUTE AND CHRONIC SCHISTOSOMA-MANSONI INFECTION

To determine the efficacy of an ELISA to diagnose and differentiate th e clinical phases of schistosomiasis, serum from patients with acute ( 11) and chronic schistosomiasis (58), from individuals infected with e ther parasites (53), and from uninfected individuals (40) was analyzed for the presence of anti-schistosomal of IgG, IgM, and IgA antibodies . Immunofluorescence for IgM and IgA antibodies was also performed on serum from all patients and controls. The IgG antibodies against worm antigen (ELISA-w) were detected in all schistosomiasis patients, with only one false-positive result. The IgA antibodies were detected by EL ISA-w in 81.8% of patients with acute disease and in only 5.9% of pati ents with chronic disease. In addition, the mean optical density value s for IgM and IgA antibodies was statistically higher in the patients with acute disease than in those with chronic disease. The results of this study show that the use of a crude adult worm extract as an ELISA antigen can provide a serologic method with high sensitivity and spec ificity for 1) the diagnosis of acute and chronic schistosomiasis and (2) the serologic distinction between the two forms of the disease.