RESUMO
Toxoplasmosis is a widespread infection in the world. Although the infection by Toxoplasma gondii is widely prevalent in humans and animals, the disease is uncommon and most of the acquired infections are asymptomatic. The important aspect of this parasitic infection is the probable danger of congenital transmission and its severe effects on the fetus. In the present descriptive study, a total of 353 samples from mentally retarded children and adolescents in rehabilitation centers in Tehran, were examined from 2001 to 2002. In order to determine the Toxoplasma antibodies, the samples were tested using an IFA technique and in some cases ELISA technique was applied as well. Fourteen percent of the examined samples were positive. In this research Toxoplasma antibody titer in 36 cases were reported as 1:100 and it was found to be 1:200, 1:400 and 1:800 in 9, 1 and 3 cases, respectively. In three cases for which the titer was reported 1:800, samples were tested applying Ig-M ELISA technique in order to determine if there was an acute infection but all tests were negative. In the current study, we did not find any significant differences in the prevalence rate between the genders, but the prevalence significantly increases with age. We used standard questionnaires for causative relation in congenital toxoplasmosis within sero-positive children and 3 cases of infection were documented during the mother's pregnancy period