Interaction Between the Neglected Tropical Disease Human Schistosomiasis and HCV Infection in Egypt: a Puzzling Relationship

Abstract

Egypt has the highest prevalence of chronic hepatitis C virus (HCV) infection and seropositivity worldwide, and it has been proposed that this enhanced susceptibility to HCV is related to coinfection with schistosomiasis. Although currently, there are no studies regarding the actual prevalence of both human schistosomiasis and schistosomiasis/HCV coinfection evidences strongly support that eliminating human schistosomiasis from Egypt is necessary to reduce both HCV prevalence and liver pathology. The present review highlights the significant impact of the neglected tropical disease human schistosomiasis on both susceptibility of Egyptians to HCV coinfection, severity of the resulting liver pathology, and poor response to antiviral therapy. The immune evasion mechanisms exerted by the HCV-NS3/4A protease domain, and the possible impact of immune evasion mechanisms exerted by proteases of larval, worm and egg stages of the parasite Schistosoma on human susceptibility to HCV infection are discussed. In addition, schistosome immune evasion mechanisms may include immunosuppression that in turn prevents clearance of HCV viremia and leads to relapsing HCV infection and severe liver pathology. I propose the generation of a replicon system from the most prevailing genotype (HCV-4a) in Egypt and establishing its replication on hepatoplastoma or immune cells in presence of bilharzial antigens. Finally, the use of a humanized small animal model that can acquire both HCV and S. mansoni infections will be important to further understand in real time the impact of coinfection on both the immune system and liver pathology.

Hepatocellular Carcinoma Related to Schistosoma mansoni Infection: Case Series and Literature Review

“… 3 , 4 , 15 , 21 Therefore, co-infected ( S. mansoni infection and HBV or HCV) patients are at higher risk for early deterioration of liver function, the development of cirrhosis, and rapid progression towards end-stage liver disease and even HCC. 20 , 21 , 23 In our sample, there were four (57.1%) patients with immunity by contact for HBV. The possible influence of this result on the disease course of these patients is unknown.…”

Does Schistosoma Mansoni Facilitate Carcinogenesis?

“…The data linking S. mansoni to cancer are insufficient and, in part, conflicting [32,33]. Nonetheless, case reports and descriptive studies from endemic regions have discussed the possibility of an association between S. mansoni infestation and cancer, including hepatocellular carcinoma (HCC) [33][34][35][36][37][38][39][40][41][42], colorectal cancer (CRC) [43][44][45][46][47][48], bladder carcinoma [49], prostate cancer [50], and follicular lymphomas [51,52]. Although S. mansoni is classified as a Group 3 carcinogen, the multiplicity of case reports, together with data from animal models and cell cultures, suggests that S. mansoni can at least predispose a patient to-or promote cancer.…”