Isolation and pathogenicity of Toxoplasma gondii in naturally infected (rustic farm) pigs in southern Brazil.

This study reported a serological test for Toxoplasma gondii infection in 100 pigs from 58 rural farms in the state of Rio Grande do Sul, Brazil. Thirty-six pigs were seropositive (IFAT≥1:64). Bioassays were performed for all 36 seropositive pigs, and 17 isolates were obtained (47.2%). Seven of these isolates (41.2%) were highly pathogenic to mice, as clinical signs of acute infection were observed, and tachyzoites were found in the peritoneal exudates, livers, and lungs. The remaining 10 isolates were able to establish a chronic infection in mice, therefore, they were not highly virulent. The results of this study indicate that pork is a potential source of T. gondii transmission to humans.