Transfusion-Transmitted Risk: High Seroprevalence and Genotypic Diversity of Toxoplasma gondii in Thalassemia Major Calls for Donor Screening Policy Review

Objectives: Patients with thalassemia major are at high risk of developing blood-borne infections, including toxoplasmosis, due to their dependence on frequent blood transfusions and underlying immune system disorders. This study was designed to investigate this hidden risk and provide data for policymaking in blood transfusion services in a region with a high endemicity. Methods: A total of 300 blood samples from thalassemia patients in northern Iran were collected. Serological testing was conducted to detect IgG and IgM antibodies. DNA extraction followed, with molecular screening performed via PCR. Finally, genotyping of T. gondii was carried out using nested PCR focused on the GRA6 gene. Results: The serological analysis revealed 59.7% of patients exhibited IgG against T. gondii, while only 0.6% tested positive for IgM. The results of the molecular screening revealed 2.7% of patients had DNA of T. gondii. The results of genetic analysis showed 75% had type II, 12.5% had type I, and 12.5% belonged to type III. Conclusions: This study provides serological and molecular evidence of a high chronic Toxoplasma gondii burden in thalassemia patients from northern Iran, an endemic region. A significant association between blood transfusion history and seropositivity, along with parasite DNA detection, suggests elevated exposure risk, though direct transfusion transmission remains unproven. Finding’s support integrating nested PCR with routine serology for diagnosing infection in this population.