Development of a new assay for the diagnosis of schistosomiasis, using cercarial antigens.

We have developed a new ELISA for detection of anti-schistosome antibodies using an extract from Schistosoma mansoni cercariae. We evaluated the new assay on serum samples sent to the Hospital for Tropical Diseases, Department of Clinical Parasitology, London, UK, by comparing it with our routinely used S. mansoni soluble egg antigen (SEA) assay. We also evaluated the new assay for cross-reactivity with a number of helminth and other infections. We demonstrate that the cercarial antigen assay is equivalent to the SEA assay for serodiagnosis of schistosomiasis in a non-endemic setting. The cercarial antigen preparation is more easily produced than SEA, and for this reason this assay may be preferred for routine clinical use and may be amenable to scaling up. Further assessment is needed before it can be recommended for use in an endemic area, as chronic disease and co-infection with other helminths are likely to be under-represented in our sample set.