Evaluation of an enzyme linked immunosorbent assay (ELISA) using Schistosoma mansoni soluble egg antigen as a diagnostic tool for Schistosoma mansoni infection in Ethiopian schoolchildren.

Evaluation of the performance of an ELISA test using S. mansoni soluble egg antigens (SEA) in relation to the standard parasitological diagnostic procedure (Kato) was conducted in a specially set up study on 400 Ethiopian schoolchildren. Faecal samples were collected on 3 successive days for preparation of Kato thick smears and two finger prick blood samples were collected onto filter paper from all the children on day 1. All helminth ova present in the triplicate Kato slides were counted and the ELISA test was carried out on both eluted serum samples. Prevalence of infection by Kato was 83.5% in the endemic area and the sensitivity and specificity of the ELISA test were 97.6% and 30.3% respectively, whereas the specificity of the ELISA in the non-endemic area was 95.5%. The main cause of 'false positivity' in the endemic area appeared to be inapparent S. mansoni infection. Because of its high sensitivity, this ELISA test will clearly be of value for seroepidemiological surveys.