Caprine toxoplasmosis in Southern Brazil: a comparative seroepidemiological study between the indirect immunofluorescence assay, the enzyme-linked immunosorbent assay, and the modified agglutination test.

This study investigated the prevalence of caprine toxoplasmosis in goat herds from Southern Brazil by the indirect immunofluorescence assay (IFA), and compared these results with the enzyme-linked immunosorbent assay (ELISA) and the modified agglutination test (MAT). In addition, possible risk factors associated with infection due to Toxoplasma gondii were determined. The serum samples evaluated were from 1,058 goats derived from 94 goat herds within the state of Paraná, Southern Brazil. Seropositivity by IFA was 30.0%, 33.3% by ELISA, and 25.3% by MAT. The risk factors associated with infection by T. gondii in goats were pasture rental, female goats, the presence of cats, and pastures shared with several goat herds. Using IFA as a standard, ELISA and MAT showed substantial concordance (kappa = 0.74 and 0.61), with sensitivities of 87 and 66.2% and specificities of 89.7 and 92.2%, respectively. These results demonstrate that caprine toxoplasmosis is endemic within the state of Paraná, Southern Brazil. In addition, the results from the three assays were relevant, without any significant differences as demonstrated due to the substantial concordance based on the kappa index.