Circulating antigens for assessing cure in schistosomiasis mansoni.

An antigen capture enzyme-linked immunosorbent assay using antibodies made in rabbits and sheep to adult Schistosoma mansoni extract antigens has been developed and evaluated as a diagnostic test for schistosomiasis. 25 of 42 patients with S. mansoni infections had detectable circulating antigen while sera from all of 45 normal subjects and patients with other parasitic infections did not react. When the 25 with antigenaemia were retested 3 months after treatment, all 21 who were cured were negative while the 4 with persisting S. mansoni eggs in their stools remained positive. Antibodies to a fractionated egg antigen (CEF6) also diminished in most patients following successful treatment, but the reduction was insufficient to predict successful therapy.