Impact of chronic schistosomiasis and HBV/HCV co-infection on the liver: current perspectives

Schistosomiasis is a public health problem in many countries. Its prevalence is increasing annually; the current infection rate is one in 30 individuals. The WHO reported that at least 206.4 million people all over the world required preventive treatments for schistosomiasis in 2016. Chronic schistosomiasis, hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infection are common in countries where schistosomiasis is endemic. The effects of the hepatotropic virus co-infection may modify the Th2-dominated granulomatous phase of schistosomal infection. These viruses induce a strong-specific T cell response, with infiltration of large numbers of specific interferon-γ-producing CD8+ cells into the liver. The outcome of liver diseases depends on the underlying causes, host immune response and concomitant infections. Co-infection of schistosomiasis with HBV/HCV infection causes advanced liver disease and worsens the outcome, especially with higher viral load titers, which increase the mortality rate through an increased incidence of liver cirrhosis and hepatocellular carcinoma. The exposure risk for HBV in patients with HCV and schistosomiasis was two and half times greater than that in CHC patients without schistosomiasis. Finally, chronic schistosomiasis and HBV/HCV co-infection have serious effects on liver pathology. Co-infection accelerates the progression of liver disease and leads to advanced liver diseases and liver failure.