Sero-Evidence Status of Toxoplasma gondii Infection in Mazandaran Province, Northern Iran: First Population-Based Regional Registry Analysis

Background: Toxoplasma gondii is one of the most common parasitic infections in humans and other vertebrates worldwide. Regional seroprevalence data are critical for targeted interventions. Weaimed to investigate serological evidence of Toxoplasma infection among patients referred to the Iranian National Registry Center for Toxoplasmosis (INRCT) at the Mazandaran University of Medical Sciences (MAZUMS). Methods: In this retrospective (descriptive-analytical) study, all patients referred to the INRCT, constitute the study population (underlying diseases/status) throughout 2021-2025. All data including demographic and some related characteristics were collected into a questionnaire and registered at the INRCT in Imam Khomeini Hospital, Sari, northern Iran. The existence of anti-Toxoplasma antibodies (IgG) was explored using a commercially available ELISA kit (PishtazTeb, Iran), based on the manufacturer’s protocol. Results: Anti-Toxoplasma IgG were detected among 862/1691 patients (50.98%). The most positive anti-Toxoplasma antibodies were in infertile women and the least were in suicide. IgG seropositivity was more common in females (66.01%) than in males (33.99%) and in 31–40 yr old patients (33.41%) in urban populations (53.71%). Conclusion: The findings highlight a high burden of T. gondii infection in northern Iran, with gender, age, and residency as key determinants. Targeted screening and preventive measures are recommended for high-risk groups, including women of reproductive age and immunocompromised populations.