Toxoplasma Gondii Infection and Alzheimer’S Disease: A Case-Control Study in a Northern Iranian Population Publisher



Rostami F ; Hashemi SA ; Shaghaghi B ; Fazaeli M ; Rezaei M ; Pagheh AS ; Arghavan MS ; Pazoki H ; Rezaei F
Source: Journal of Parasitic Diseases Published:2026

Abstract

Despite extensive research, the causes and progression of Alzheimer’s disease remain incompletely understood. Given the strong tropism of Toxoplasma gondii for the central nervous system, this study aimed to investigate the association between the presence of anti-T. gondii antibodies and Alzheimer’s disease. We selected individuals with Alzheimer’s disease from Mazandaran province, with a control group consisting of individuals without a history of neurological or psychiatric disorders. A structured questionnaire was used to record sociodemographic and behavioral characteristics. Serum samples from all subjects were tested for specific IgM and IgG antibodies against T. gondii using an enzyme immunoassay. Multivariate logistic regression was used to calculate adjusted odds ratios (ORs). The study included 115 Alzheimer’s patients and 115 controls. The seroprevalence of IgG antibodies against T. gondii was significantly higher in Alzheimer’s patients than in healthy controls (26.1% vs. 9.6%, p < 0.05), yielding an adjusted odds ratio of 2.89 (95% CI 1.08–7.83). Gender, education level, and occupation were also identified as significant factors. No IgM-positive samples were detected. A key limitation is the significant age difference between the patient and control groups. The findings indicate a significant association between T. gondii infection and Alzheimer’s disease. Further research is needed to confirm this relationship and explore potential mechanisms. © Indian Society for Parasitology 2026.