Association between Toxoplasma gondii infection and history of blood transfusion: a case-control seroprevalence study.

Objectives This study was performed to determine the association between seropositivity to Toxoplasma gondii and a history of blood transfusion. Methods Patients who had undergone blood transfusion (n=410) and age- and sex-matched controls who had not undergone blood transfusion (n=1230) were examined for anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. Results Anti-T. gondii IgG antibodies were detected in 57 (13.9%) patients and in 129 (10.5%) controls with a borderline difference [odds ratio (OR)=1.37, 95% confidence interval (CI)=0.98-1.92]. High anti-T. gondii IgG antibody levels (>150 IU/mL) were found in 27 (47.4%) of the 57 anti-T. gondii IgG-positive patients and in 37 (28.7%) of the 129 anti-T. gondii IgG positive controls with a significant difference (OR=2.23, 95% CI=1.17-4.26). Anti-T. gondii IgM antibodies were found in 13 (22.8%) of the 57 seropositive patients and in 37 (28.7%) of the 129 seropositive controls, but the difference was not significant (OR=0.73, 95% CI=0.35-1.52). Seroprevalence was significantly higher in patients aged >50 years than in controls of the same age and in female patients than in female controls. Conclusions These findings indicate that a history of blood transfusion is a risk factor for T. gondii infection.