Toxoplasmosis and Alzheimer: can Toxoplasma gondii really be introduced as a risk factor in etiology of Alzheimer?

Abstract

Alzheimer is a progressive neurological disease that results in irreversible loss of neurons and includes about two thirds of all cases of dementia. Toxoplasma gondii may be an important infectious agent involved in neurodegenerative diseases. The aim of this study was to investigate the correlation between Toxoplasma as an etiologic agent in the progress of Alzheimer's disease. This case control study was conducted on 75 Alzheimer's patients and 75 healthy volunteers. Blood samples were obtained and anti-Toxoplasma IgG and IgM tests were done by using ELISA technique. DNA was extracted from buffy coat and then GRA6 gene and SAG2 loci were amplified by PCR and nested PCR, respectively. Chi-square, Fisher's test, and binary logistic regression were used for data analysis. A percentage of 61.3 % of Alzheimer's patients and 62.6 % of healthy volunteers were positive for anti-Toxoplasma IgG but all participants were negative for anti-Toxoplasma IgM. There were no significant differences between Alzheimer's patients with their controls in terms of anti-Toxoplasma IgG antibody (P = 0.5). Due to lack of positive IgM sample, results of the molecular methods were negative by GRA6 and SAG2 fragments amplification. This result shows that, infection with T. gondii cannot be considered as a risk factor for etiology and developing Alzheimer's disease.

Toxoplasma Gondii Infection and Related Risk Factors Among Blood Donors in Northwest Iran

“…However, it was in contrast with the findings of Elhence et al in India (12). Our study limitation was the 4 Arch Clin Infect Dis. 2017; 12(2):e62005.…”

“…gondii infection, it is usually mild and self-limiting in immunocompetent hosts (2)(3)(4)(5)(6). However, toxoplasmosis can cause severe and fatal disease in immunocompromised patients and congenitally infected fetuses and newborns (2,(7)(8)(9).…”

Polymicrobial Infections In Brain Tissue From Alzheimer’s Disease Patients

“…Finally, the possibility that the protozoan T. gondii could be involved in the etiology of AD has been considered 39 . However, seroprevalence of antibodies against this protozoan is similar in controls and AD patients 40, 41 . Therefore, we used nested PCR using primers to amplify the SAG2 locus 50 .…”

“…In addition, other pathogens such as Cytomegalovirus and Helicobacter have been considered as the causative agent of AD 7 . Finally, the possibility that a protozoan such as Toxoplasma gondii is involved in AD has been posited 39 , but not experimentally supported 40, 41 .…”

Reexamining Chronic Toxoplasma gondii Infection: Surprising Activity for a “Dormant” Parasite

“…An emerging body of evidence suggests that the presence of an established chronic infection may contribute to the pathogenesis of diverse neurological conditions including schizophrenia [57, 58], epilepsy [59], and neurodegenerative conditions [60–62]. These studies and their impact on our understanding of chronic toxoplasmosis in human disease are reviewed elsewhere [57, 59, 60, 62]. In addition, evidence from rodent studies suggests that the chronic toxoplasmosis results in the modulation of the host’s behavior (reviewed in [63, 64]).…”