Hepatitis E virus (HEV) is the causative agent of hepatitis E.
Globally, approximately 939 million corresponding to 1 in 8 individuals have ever experienced HEV infection. About 15ā110 million individuals have recent or ongoing HEV infection.The virus particle was first seen in 1983, but was only molecularly cloned in 1989.
Hepatitis is inflammation of the liver tissue. Some people or animals with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pain, and diarrhea. Hepatitis is acute if it resolves within six months, and chronic if it lasts longer than six months. Acute hepatitis can resolve on its own, progress to chronic hepatitis, or (rarely) result in acute liver failure. Chronic hepatitis may progress to scarring of the liver (cirrhosis), liver failure, and liver cancer.
Hepatitis is most commonly caused by the virus hepatovirus A, B, C, D, and E. Other viruses can also cause liver inflammation, including cytomegalovirus, EpsteināBarr virus, and yellow fever virus. Other common causes of hepatitis include heavy alcohol use, certain medications, toxins, other infections, autoimmune diseases, and non-alcoholic steatohepatitis (NASH). Hepatitis A and E are mainly spread by contaminated food and water. Hepatitis B is mainly sexually transmitted, but may also be passed from mother to baby during pregnancy or childbirth and spread through infected blood. Hepatitis C is commonly spread through infected blood; for example, during needle sharing by intravenous drug users. Hepatitis D can only infect people already infected with hepatitis B.
Hepatitis E is inflammation of the liver caused by infection with the hepatitis E virus (HEV); it is a type of viral hepatitis. Hepatitis E has mainly a fecal-oral transmission route that is similar to hepatitis A, although the viruses are unrelated. HEV is a positive-sense, single-stranded, nonenveloped, RNA icosahedral virus and one of five known human hepatitis viruses: A, B, C, D, and E.
Like hepatitis A, hepatitis E usually follows an acute and self-limiting course of illness (the condition is temporary and the individual recovers) with low death rates in resource-rich areas; however, it can be more severe in pregnant women and people with a weakened immune system, with substantially higher death rates. In pregnant women, especially in the third trimester, the disease is more often severe and is associated with a clinical syndrome called fulminant liver failure, with death rates around 20%. Whereas pregnant women may have a rapid and severe course, organ transplant recipients who receive medications to weaken the immune system and prevent organ rejection can develop a slower and more persistent form called chronic hepatitis E, which is so diagnosed after 3 months of continuous viremia. HEV can be clustered genetically into 8 genotypes, and genotypes 3 and 4 tend to be the ones that cause chronic hepatitis in the immunosuppressed.