Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 25, 2001
Publication Date: N/A
Interpretive Summary: Infection by the protozoan (single-celled) parasite, Toxoplasma gondii, are widely prevalent in humans and anmals. It causes mental retardation and loss of vision in congenitally-infected children and abortion in livestock. There is a single species of the parasite in the genus Toxoplasma, T. gondii. Scientists at the Beltsville Agricultural Research Center and the CDC, Atlanta, Georgia describe a new high resolution system for typing strains of T. gondii. These results will be of interest to biologists, parasitologists and geneticists.
High resolution typing of Toxoplasma gondii is essential to understand the effect of genetic differences among strains on the variation in disease manifestation and transmission patterns. Current typing methods discern 3 lineages with minimal within-lineage variation. Described here are 6 new variable loci. These loci, including a minisatellite and 5 microsatellites, were more polymorphic than allozymes, RFLPs, and sequence variation in introns. Most importantly, these loci revealed, for the first time, substantial within-lineage variation that was over 6-fold higher than that detected by other markers. Genotyping at these loci facilitates classification of isolates beyond the lineage level.