Multi-locus DNA sequencing of Toxoplasma gondii isolated from Brazilian pigs identifies genetically divergent strains.

Five Toxoplasma gondii isolates (TgPgBr1-5) were isolated from hearts and brains of pigs freshly purchased at the market of Campos dos Goytacazes, Northern Rio de Janeiro State, Brazil. Four of the five isolates were highly pathogenic in mice. Four genotypes were identified. Multi-locus PCR-DNA sequencing showed that each strain possessed a unique combination of archetypal and novel alleles not previously described in South America. The data suggest that different strains circulate in pigs destined for human consumption from those previously isolated from cats and chickens in Brazil. Further, multi-locus PCR-RFLP analyses failed to accurately genotype the Brazilian isolates due to the high presence of atypical alleles. This is the first report of multi-locus DNA sequencing of T. gondii isolates in pigs from Brazil.