Seroprevalence of <i>Toxoplasma gondii</i> Infection in Cancer Patients in Southwest Iran: A Case-Control Study

Background: Cats are the definitive hosts of Toxoplasma gondii, while humans and livestock can serve as intermediate hosts. The infection is usually asymptomatic in immunocompetent individuals but can cause serious consequences, such as encephalitis, in immunocompromised patients, including those with cancer. Objectives: Considering the potential risk of severe complications in immunocompromised patients, this study aimed to investigate the seroprevalence of T. gondii in cancer patients compared to a control group and assess related risk factors. Methods: This case-control study included 128 cancer patients admitted to educational hospitals in Abadan and Khorramshahr in 2021. The control group comprised 128 outpatients without underlying diseases from the same hospitals. A questionnaire including demographic information and toxoplasmosis risk factors was completed for each participant. Five milliliters of blood samples were collected and checked for IgG and IgM antibodies against T. gondii by ELISA. Data were analyzed using SPSS version 19, and descriptive statistics, including frequency and percentage, were used. A P-value < 0.05 was considered significant. Results: Among cancer patients, 51 (39.84%) were positive for IgG, and 3 (2.34%) patients were positive for IgM. In the control group, 60 (46.88%) and 4 (3.13%) were positive for IgG and IgM, respectively. No significant difference in seroprevalence rate was found between the groups. In those over 60 years, seroprevalence was higher. In the control group, female gender, living in rural areas, and consumption of untreated drinking water were significantly associated with infection. Conclusions: Despite the lack of a significant association between cancer and toxoplasmosis, the immunosuppressed condition of cancer patients, together with the high regional prevalence, demonstrates why T. gondii should be monitored as an opportunistic infection.