Comparison of indirect immunofluorescent antibody test and modified direct agglutination test methods for detection of Toxoplasma gondii antibodies in adult sheep in Spain.

A total of 2306 serum samples obtained from adult sheep were analysed for Toxoplasma gondii IgG antibodies by modified direct agglutination test and indirect immunofluorescence assay test. Similar results were obtained with both procedures (seroprevalence of 35.27% for modified direct agglutination test and 33.72% for indirect immunofluorescence assay test at dilution 1:80), but some differences in relation to sample dilution were registered. All the titers assayed (dilution two-fold from 1:40 to 1:320) can be used in diagnosis with both procedures, but titers 1:80 are recommended for screening studies in ovine flocks.