Isolation and genotyping of Toxoplasma gondii from pregnant dairy cows (Bos taurus) slaughtered.

The current study aimed to evaluate serology, and isolate and genotype Toxoplasma gondii strains from pregnant dairy cows, slaughtered in an abattoir for human consumption, and their fetuses. Blood from 60 pregnant dairy cows and blood and tissue samples (brain, lung, heart, and liver) from their fetuses were collected and analyzed in a mouse bioassay. Antibodies against T. gondii were observed in 48.3% of cows and 3.7% of fetuses (IFAT, titers ≥ 50 for cows and 25 for fetuses were considered positive). Fourteen fetuses (23.3%) and six cows (10.0%) were identified as positive in the bioassay. T. gondii was isolated from a blood sample of a cow older than 4 years old in the 6th month of pregnancy, and from a blood sample of a fetus in the 6th month of gestation. These isolates were identified by polymerase chain reaction (PCR) as being of T. gondii and both strains showed type II alleles for all PCR-restriction fragment length polymorphism (PCR-RFLP) markers tested. T. gondii type II strain from cattle was isolated for the first time in Brazil. The current study also showed that transplacental transmission of T. gondii naturally occurs in dairy cows (23.3%) from Southern Brazil.