Hepatitis E virus (HEV) is one of the 7 viruses with mainly hepatic tropism. HEV determines 20 million new infections worldwide every year, 3.4 million acute hepatitis E and 44,000 deaths in 2015 (3.3% of the mortality due to viral hepatitis). Transmitted by the digestive tract mainly (fecal- orally, particularly by water infected with feces), the virus reaches the liver where it does not have a direct cytolytic effect, but immunological phenomena, especially cellular, activated by the replication of the virus in the hepatocytes. Clinically, over 95% of cases of HEV infection are asymptomatic and sel- limiting; in immunocompetent patients in tropics HEV can cause acute hepatitis with clinical features. On rare situations the infection can result in a severe, fulminant hepatitis with acute liver failure. In immunocompromised patients (organ transplant recipients, hematologic malignancies, HIV-infected) HEV may determine chronic hepatitis. In pregnant women or the elderly people or people with underlying liver disease HEV can cause fulminant forms which can become fatal (E.g.: 30% deaths among pregnant women in some parts of the world). Acute and chronic E hepatitis may be accompanied by extrahepatic manifestations: neurological, kidney, pancreatic, hematological diseases, autoimmune diseases with a pathogenesis not fully elucidated.
Part of the book: Liver Pathology