Dye-immunoassay for the diagnosis of schistosomiasis mansoni

A novel serological method dot-dye immunoassay (DIA) is described and the system is tested for the diagnosis of schistosomiasis mansoni. Sera of 32 chronic Schistosoma mansoni-infected patients and 12 non-infected individuals were simultaneously tested for the presence of IgG antibodies against soluble egg antigen (SEA) by DIA and enzyme-linked immunosorbent assay (ELISA). Optical density (OD) readings using 2,2′azino-bis 3-ethylbenzthiazoline-6-sulphonic acid (ARTS) substrate in ELISA (ODABTS) and dye conjugate in DIA (ODDYE) showed the coefficient of correlation of Pearson to be 0.91 (P < 0.0001). The DIA method has one step less than the ELISA technique, thus shortening the time of the test. The advantages of textile dyes as reaction indicators in the DIA method also include the absence of contact with potentially hazardous substrates, mostly employed in ELISA. Furthermore, colloidal dyes are less expensive than enzyme conjugates and substrates. The DIA method is a reliable and simple alternative for the serological diagnosis of Schistosoma mansoni infection.