Validation of the specificity of the modified agglutination test for toxoplasmosis in pigs.

Serum samples from Toxoplasma gondii-negative pigs infected with protozoa, helminths and viruses, and from fetal pigs were examined for cross reacting antibodies to T. gondii by the use of the modified agglutination test (MAT). Nonspecific reactions with T. gondii antigen were not found in 1:10 dilutions of sera from eight pigs experimentally infected with Sarcocystis miescheriana, 11 pigs infected with Ascaris suum, three pigs infected with Trichuris suis, ten pigs infected with Trichinella spiralis, nine pigs infected with various porcine viruses, six gnotobiotic pigs, and 82 fetal pigs. Antibodies were also not found in 1:25 dilution of sera from 200 naturally aborted fetal pigs. Thus, evidence for cross reactivity to T. gondii with unrelated or related organisms using the MAT was not found.