The genotype of Toxoplasma gondii strains causing ocular toxoplasmosis in humans in Brazil

Am J Ophthalmol. 2005 Feb;139(2):350-1. doi: 10.1016/j.ajo.2004.07.040.


Purpose: To determine Toxoplasma gondii genotype in scars of retinochoroiditis in humans.

Design: Immunopathology analysis.

Methods: DNA was isolated from retinochoroidal specimens taken from the borders of the scars from eye bank eyes as well as enucleated eyes from uveitis patients with retinochoroidal toxoplasmic scars. The SAG2 region was amplified by polymerase chain reaction and analyzed by restriction fragment length polymorphism.

Results: Of the 92 eyes studied, 9 had toxoplasmic scars. All of them, as well as the 2 enucleated eyes, disclosed the presence of type I parasites by the gel electrophoresis analysis of the restriction fragment length polymorphism from SAG2.

Conclusion: These results suggest that type I strain seems to be responsible for the ocular infections in the population studied.

MeSH terms

  • Animals
  • Antigens, Protozoan / genetics
  • Brazil / epidemiology
  • Chorioretinitis / epidemiology
  • Chorioretinitis / parasitology*
  • DNA, Protozoan / analysis*
  • Eye Banks
  • Eye Enucleation
  • Genotype*
  • Humans
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Protozoan Proteins / genetics
  • Toxoplasma / genetics*
  • Toxoplasmosis, Ocular / epidemiology
  • Toxoplasmosis, Ocular / parasitology*


  • Antigens, Protozoan
  • DNA, Protozoan
  • Protozoan Proteins
  • surface antigen P22, Toxoplasma