Background: The evaluation of toxoplasma chorioretinitis is of utmost importance in the early diagnosis, treatment, and prevention of visual problems that can otherwise lead to permanent blindness. The aim of this study was to determine the prevalence of toxoplasma chorioretinitis among primary school students in Tehran. Material/Methods: This cross-sectional study involved 1529 healthy primary school students from the 19 school districts in Tehran (2003-2004). The mean age was 9.7+/-1.55 years. Serum anti-toxoplasma level (IgG) was measured by quantitative chemiluminescent immunoassay (CLIA) and students with positive result were referred to an ophthalmologist for further evaluation. Results: Of the 1529 students, 1377 (90%) had negative and 152 (10%) had positive serum titers. Seroprevalence was higher in boys (12%) and increased with age. Sixty-five students (43%) were referred to an ophthalmologist and acute chorioretinitis was diagnosed in a nine-year-old boy who was given anti-toxoplasma medication and was free of any active lesion one year later. Conclusions: Seroprevalence was lower than in some other studies performed in Iran, which can be attributed to climate conditions and urban life. Considering the low rate of visits to an ophthalmologist, this indicates the need for increased awareness regarding the disease and its complications.

Keywords: Child, Chorioretinitis - microbiology, Cross-Sectional Studies, Immunoassay, Immunoglobulin G - blood, Iran - epidemiology, Prevalence, Seroepidemiologic Studies, Toxoplasma