Hepatitis Virus

The most common causes of viral hepatitis are the five unrelated hepatotropic viruses hepatitis A, B, C, D, and E.

(Other viruses can also cause liver inflammation, including cytomegalovirus, Epstein-Barr virus, and yellow fever. There also have been scores of recorded cases of viral hepatitis caused by herpes simplex virus.)

Hepatovirus A (HAV) is a species of virus in the order Picornavirales, family Picornaviridae, genus Hepatovirus. It is not enveloped and contains a positive-sense single-stranded RNA packaged in a protein shell. This virus causes the disease hepatitis A.

Hepatitis B virus (HBV), is a partially double-stranded DNA virus, a species of the genus Orthohepadnavirus and a member of the Hepadnaviridae family of viruses. This virus causes the disease hepatitis B. This virus is one of the smallest enveloped animal viruses. It consists of an outer lipid envelope and an icosahedral nucleocapsid core composed of protein. The nucleocapsid encloses the viral DNA and a DNA polymerase that has reverse transcriptase activity similar to retroviruses. The outer envelope contains embedded proteins which are involved in viral binding of, and entry into, susceptible host cells.

Hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family Flaviviridae. This virus is the cause of hepatitis C and some cancers such as liver cancer (hepatocellular carcinoma, abbreviated HCC) and lymphomas in human.