Fascioliasis and COVID-19: A Case-Control Study in Iran

Background: Human Fascioliasis is a zoonotic infection caused by the adult stage of Fasciola species. Fasciola hepatica is a parasite that, following living in its vertebrate host, reduces the host's inflammatory immune responses to infectious diseases, including COVID-19. Therefore, because of the completely unproven and limited data on this issue, we decided to evaluate the prevalence of antibodies against this parasite in patients admitted to the hospital due to relatively severe symptoms of COVID-19. Methods: : This cross-sectional study was conducted on the serum samples of 182 patients with COVID-19 disease who were diagnosed by PCR test and 210 healthy subjects in Alborz Province, Iran between March and June 2020. Anti- Fasciola antibodies status was determined in all serum samples, using ELISA technique. A self-developed questionnaire was used to measure demographic information. Results: : The frequency of Fasciola infection was found to be significantly higher in COVID-19 patients as compared to healthy control (n = 4, 2.2%, n = 9, 4.3%; respectively) ( P = 0.041). There was no significant difference between COVID-19 patients and control group in age, education, and gender ( P > 0.05). Conclusions: : This study indicates that a significant association between Fasciola hepatica seropositivity and COVID-19 disease. Our finding suggests that Fasciola infection may be able to lead to decreased immune responses, thereby reducing the severity and symptoms of COVID-19 disease.