The word "hepatitis" means inflammation of the liver. Toxins, certain drugs, some diseases, heavy alcohol use, and bacterial and viral infections can all cause hepatitis. Hepatitis is also the name of a family of viral infections that affect the liver. The most common types are hepatitis A, hepatitis B, and hepatitis C. Below is an overview of the hepatitis viruses from the Centers for Disease Control's National Prevention Information Network.
Hepatitis A Virus
Hepatitis A is a liver disease caused by the hepatitis A virus (HAV). HAV infection produces a self-limited disease that does not result in chronic infection or chronic liver disease. HAV infection is primarily transmitted by the fecal-oral route, by either person-to-person contact or through consumption of contaminated food or water. Hepatitis A vaccination is the most effective measure to prevent HAV infection and is recommended for all children at age 1, certain international travelers, and others at risk for HAV infection.
Hepatitis B Virus
Hepatitis B is a serious liver infection caused by hepatitis B virus (HBV). HBV infection can cause acute illness and lead to chronic or lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure, and death. HBV is transmitted through percutaneous (puncture through the skin) or mucosal contact with infectious blood or body fluids. Hepatitis B vaccination is the most effective measure to prevent HBV infection and its consequences and is recommended for all infants and others at risk for HBV infection.
Hepatitis C Virus
Hepatitis C is a liver disease caused by the hepatitis C virus (HCV) that sometimes results in an acute illness, but most often becomes a silent, chronic infection that can lead to cirrhosis (scarring), liver failure, liver cancer, and death. Chronic HCV infection develops in a majority of HCV-infected persons, most of whom do not know they are infected since they have no symptoms. HCV is spread by contact with the blood of an infected person. There is no vaccine for hepatitis C.
Hepatitis D Virus
Hepatitis D is a serious liver disease caused by the hepatitis D virus (HDV), and only occurs in people already infected with hepatitis B, since HDV needs the hepatitis B virus to replicate. HDV is transmitted through percutaneous (puncture through the skin) or mucosal contact with infectious blood.
Hepatitis E Virus
Hepatitis E is a liver infection caused by the hepatitis E virus (HEV) that usually results in a self-limited disease. HEV infection is primarily transmitted by the fecal-oral route, mostly through consumption of contaminated water. While rare in the United States, hepatitis E is common in many parts of the world. There is currently no FDA-approved vaccine for hepatitis E.
For more information about hepatitis generally, see the Viral Hepatitis information page maintained by the Centers for Disease Control and Prevention. The American College Health Association includes discussion and recommendations regarding both Hepatitis A and Hepatitis B on its list of Recommendations for Institutional Prematriculation Guidelines (January 2009).