A SIMPLE AND ECONOMIC SLIDE MICRO-IMMUNOENZYMATIC (MICRO-SIA) TEST FOR EPIDEMIOLOGIC STUDIES OF TOXOPLASMOSIS

A slide micro-immunoenzymatic assay (micro-SIA) to detect antibodies t o non-particulate Toxoplasma gondii antigens is described. This assay allo,vs the diagnosis of toxoplasmosis infection in about 1 hr. Twenty -four determinations can be performed per slide. Five hundred ng of an tigen and 5 or 10 mu l drop of each reactive are necessary per well. T he clear contrast of colours obtained for negative and positive sera a fter the test is finished, allows direct discrimination of the results . However, it is possible to quantify the results of the reaction usin g a minireader. Sei-a dilution cutoff value, determined as the most fr equent titre for the general population, is 1:100. The toxoplasma micr o-SIA correlates well with indirect immunofluorescence (IIF), its sens itivity is at least three times as much as IIF. The test has an intra and inter assay variation coefficient of 5.46% and of 6.24% respective ly Sera obtained at random from argentinian people were analyzed and a 56% of infection was found. The main features of the Toxoplasma micro -SIA are its simplicity, sensitivity, reproducibility, and the virtual absence of background making it very suitable for screening tests.