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BACKGROUND: By 27 June 2020, almost half a million people had died due to COVID-19 infections. The susceptibility and severity of infection vary significantly across nations. The contribution of chronic viral and parasitic infections to immune homeostasis remains a concern. By investigating the role of interferon (IFN)-γ, we conducted this study to understand the connection between the decrease in numbers and severity of COVID-19 cases within parasitic endemic regions. Our research included 375 patients referred to hospitals for diagnosis of COVID-19 infection. Patients were subjected to full investigations, in particular severe acute respiratory syndrome coronavirus-2 nucleic acid and Toxoplasma IgM and IgG antibody detection, stool examination, and quantitative IFN-γ measurement. RESULTS: The majority of the studied cases had chest manifestation either alone (54.7%) or in association with gastrointestinal (GIT) manifestations (19.7%), whereas 25.6% had GIT symptoms. We reported parasitic infections in 72.8% of mild COVID-19 cases and 20.7% of severe cases. Toxoplasma gondii, Cryptosporidium, Blastocyst, and Giardia were the most common parasitic infections among the COVID-19 cases studied. CONCLUSION: The remarkable adaptation of human immune response to COVID-19 infection by parasitic infections with high levels of IFN-γ was observed in moderate cases compared with low levels in extreme cases. The potential therapeutic efforts aimed at the role of parasitic infection in immune system modulation are needed if this hypothesis is confirmed.
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INTRODUCTION: Toxoplasma gondii is an intracellular protozoan that may disrupt the traditional cell barriers against cancer, allowing the accumulation of oncogenic mutations over time. Our research aimed to explore the relationship between T. gondii infection and tumor development. METHODOLOGY: The anti-T. gondii IgG and IgM antibodies were tested for156 patients with tumors (51 with breast cancer, 20 with hepatoma, 20 with larynx carcinoma, 20 with squamous cell carcinoma of bone, 16 with lymphoma, 13 with brain tumor, 4 with bladder cancer and 12 with benign uterine tumor) and 90 healthy controls by using electrochemiluminescence immunoassay. Tissue specimens were collected from T. gondii seropositive cases for histological and immunohistochemistry (IHC) examinations. RESULTS: The seroprevalence of human toxoplasmosis in the Sharkia Governorate, Egypt is significantly correlated with various types of tumors: breast cancer in 49 subjects (96.1%), and squamous cell carcinoma of bone in 16 subjects (80%). It was also present in nine cases of brain tumors. Anti-Toxoplasma IgG was detected in seven cases of liver tumors and one-quarter of bladder cancer. The anti- Toxoplasma IgM was present in three patients with benign uterine tumors, one patient with a bone tumor and two patients with breast cancer. Toxoplasma cysts were detected in immunostained brain sections. CONCLUSION: The correlation between T. gondii infection and tumors was established by this study indicating a significant emerging role of human toxoplasmosis in the etiology or existence of particular types of tumors.