Associations between Toxoplasma gondii Infection and Multiple Sclerosis: A Case-Control Seroprevalence Study

Currently, there are conflicting reports on the associations between Toxoplasma gondii infection and multiple sclerosis (MS) in humans. In the present study, a case-control study was carried out to assess associations between seropositivity to T. gondii infection and MS.

This case-control study was carried out on 200 MS patients (cases) attended in Sina Hospital affiliated to Tehran University of Medical Sciences, Tehran, Iran, and 200 healthy subjects from the general population of the same city, March to July 2017. Blood samples were collected from individuals and were examined using Enzyme-linked immunosorbent assay (ELISA) for the presence of T. gondii IgG antibodies and the IgG-positive samples were further analyzed for specific anti-T. gondii IgM.

The overall seroprevalence of anti-T. gondii IgG was 44.2% (177/400) in 121 (60.5%) sera of the 200 MS patients (cases) and 56 (28.0%) sera of the 200 controls (OR = 3.94; 95% CI: 2.59-5.99; P < 0.001). Seroprevalence of T. gondii infection in MS patients increased significantly with increasing of age (P < 0.001). In the control group, no statistically significant differences were seen between the seroprevalence of T. gondii infection in various age groups (P = 0.858). Moreover, no statistically significant relationships were reported between the seropositivity to T. gondii and the sex for the cases and controls (P>0.05). Anti-T. gondii IgM antibodies were not detected in anti-T. gondii IgG positive patients.

T. gondii infection might be a probability risk factor for MS. However, further studies are necessary to describe clearly the roles of T. gondii infection in MS.