One point dilution enzyme-linked immunosorbent assay (ELISA) for Toxoplasma gondii seroepidemiological surveys.

Abstract

A one point dilution enzyme-linked Immunosorbent assay (ELISA) procedure suitable for determining immunoglobulin G (IgG) antibody levels to Toxoplasma gondii (T. gondii) in community seroepidemiological surveys is described. A two-fold serial dilution ELISA procedure was first used to determine the IgG titers in 56 and 83 sera earlier screened by the Sabin-Feldman dye test (DT) and the indirect hemagglutination test (IRA), respectively. The regression rate of the results by the DT and ELISA was 0.92. Comparison of the results by the IHA and the two-fold serial dilution ELISA gave regression coefficient of 0.92. Using the absorbance values for the test sera at dilutions of 1: 20, standard curves made by plotting the optical density versus the corresponding dilution factor of a control sera were used to estimate the antibody levels. The regression coefficient of the results by the two-fold serial dilution method and those by the curves for sera with titers of up to 1: 320 was 0.97. The curves could not, however, estimate accurately the antibody level in sera with titers above 1: 320. The one point dilution ELISA described is a useful epidemiological tool for the screening of IgG antibody to Toxoplasma gondii in the community. However, larger series are required to confirm our observations. ----Toxoplasma gondii ; ELISA ; seroepidemiological survey A number of serological tests have been described for the detection of antibody to Toxoplasma gondii. In choosing a diagnostic test, however, the specificity, sensitivity, safety, cost and time required to get the results are some of the major determining factors. In this regard, the enzyme linked immunosorbent assay (ELISA), has been noted to offer a combination of the best qualities (Wisdom 1976). Although originally described as a single tube, photometrically

Evaluation of ELISA for the Detection of Toxoplasma Antibodies in Swine Sera

“…Although ELISA has been reported to be a rapid, sensitive and easily performed test for routine serology and for screening of toxoplasma antibodies (Walls et at. 1977, Camargo et al 1978, Woodward 1982, Waltman et al 1984, Pallangyo et al 1985, Uggla 1986, it has also been considered technically more difficult than LA, IHAT or [FAT (Wilson et al 1987). The performance of ELISA needs special equipment and a skilled staff.…”