Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2010
Publication Date: January 10, 2011
Citation: Frazao-Teixeira, E., Sundar, N., Dubey, J.P., Grigg, M.E., De Oliveira, F.C.R. 2011. Multi-locus DNA sequencing of Toxoplasma gondii isolated from Brazilian pigs identifies genetically divergent strains. Veterinary Parasitology. 175:33-39.
Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating undercooked meat from infected animals and food and water contaminated with oocysts. In the present study, scientists describe for the first time in detail genetic characteristics of Toxoplasma strains isolated from pigs from Brazil. The results will be of interest to biologists, parasitologists, and veterinarians.
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 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 genetic sequencing of T. gondii isolates in pigs from Brazil.