Successful application of the diffusion-in-gel-enzyme-linked immunosorbent assay (DIG-ELISA) in onchocerciasis

The recently described DIG-ELISA test was evaluated on 38 sera from patients with onchocerciasis, using a soluble, crude extract of Onchocerca volvulus dissected out from glycerol-preserved nodules. Results showed that the diameters of the orange-yellow antibody-antigen reaction zones obtained with infected sera were significantly greater than those obtained with normal human sera. A close correlation was observed between the diameters of the reaction zones and antibody concentration (expressed as log of the serum dilution), indicating the potential utility of this test in the quantitative determination of serum antibodies. Because the test is easily performed, it can be used under field conditions when an immediate quantitative determination of serum antibodies is needed.