Prevalence of Anti-Toxoplasma gondii Antibodies in Young Iranians: The CASPIAN III Study

Toxoplasmosis is a worldwide neglected tropical and sub-tropical infection caused by Toxoplasma gondii (T. gondii). Most of the previous studies on the seroprevalence of T. gondii in Iran have been done at provincial level and on specific populations, including pregnant females. Socioeconomic parameters are associated with the prevalence of this disease. In this study, the authors evaluated the presence of anti-T. gondii antibodies and the related risk factors in Iranian adolescents.
This was a cross-sectional study on serum samples from the third Iranian national school-based survey (the CASPIAN III study), which included 10- to 18-year-old students. Participants were selected by multistage sampling from 27 Iranian provinces. In this study, serum samples of 882 adolescents from 16 provinces were randomly selected and examined for IgG and IgM antibodies against T. gondii by the Enzyme Linked Fluorescent Assay (ELFA). Demographic and socioeconomic factors related to T. gondii infection were gathered using the global school-based health survey (GSHS) questionnaire.
The overall T. gondii IgG and IgM seropositivity was 56.3% (95% CI: 53.4 to 59.2) and 3.7% (95%CI: 2.7 to 4.9), respectively. In multivariate logistic regression model, family size was statistically associated with seroprevalence of anti T. gondii IgG. Living in crowded households (households with more than 4 people vs. households with less than 4 people) increased the risk of seropositivity of T. gondii (OR: 1.40, 95% CI: 1.10 to 1.99).
The results of this study indicate that about 40% of Iranian adolescents have not had contact with the T. gondii, thus the risk of congenital toxoplasmosis might be high in young females. Also, household size was the main factor associated with T. gondii infection. Preventive strategies and health education in Iranian adolescents are recommended.