Cystatin capture enzyme-linked immunosorbent assay for serodiagnosis of human schistosomiasis mansoni.

To diagnose human schistosomiasis mansoni, the current study tested an ELISA system that employs indirectly, through a chicken cystatin capture agent, the S. mansoni cysteine proteinases as antigens to detect IgG anticysteine proteinases. The study examined 40 patients with S. mansoni, 20 patients with parasitic infections other than schistosomiasis mansoni, and 20 apparently healthy individuals with no parasitic infections. The results showed that the cystatin capture ELISA gave a high sensitivity of 100% even in patients with low egg count. A similar high sensitivity was also recorded with conventional ELISA using SWAP alone without presensitization of ELISA plate with cystatin. Moreover, the capture ELISA showed no cross reactions with patients with other parasitic infections or normal individuals giving a 100% specificity, while the conventional ELISA using SWAP alone gave a lower specificity of 85%. The cystatin capture ELISA was found to be an easy, highly sensitive and specific serological method for the diagnosis of human schistosomiasis mansoni without the need of purified proteinases antigens.