Seroepidemiology and Risk Factors of Toxoplasma gondii in Iranian COVID-19 Patients: A Case-Control Study.

Background: Theoretically, there is a possible association between emerging SARS-CoV-2 infection and parasites such as Toxoplasma gondii. We aimed to evaluate the seroepidemiology of T. gondii in COVID-19 patients and the control group as well as its correlation with risk factors.

Methods: Totally, 450 sera samples were taken from COVID-19 positive patients and controls from the Tehran, Karaj, and Shiraz cities, Iran. Anti-T. gondii IgG and IgM were evaluated using the ELISA technique. After two months, the participants were followed for recovery or non-recovery and even death. The association between seroprevalence and severity of viral infection as well as other risk factors was statistically estimated.

Results: IgG prevalence in patients and healthy individuals was 59.11% and 61.77%, respectively; these values were estimated at 2.22% and 0% for IgM, respectively. There was no significant association between the prevalence of IgG with COVID-19 infection, while this association was statistically significant for IgM prevalence. The Karaj had the highest prevalence, and a significant association was observed between the seroprevalence and some variables.

Conclusion: Despite the non-significant association between the chronic phase of T. gondii (sero) prevalence and COVID-19 symptomatic forms, the parasite prevalence was estimated remarkable and the viral infection and parasite-related acute phase antibodies relationship was estimated to be statistically significant. Due to immunosuppressive therapies for this viral inflammatory infection, it makes it more difficult to interpret the results, and because of the vulnerability of the immune system of these individuals, toxoplasmosis is likely to be hazardous in them; therefore, screening for this parasitic complication seems necessary.