Viral Hepatitis and the Viruses that Cause It

Five Hepatitis Virus Types


Viral hepatitis is a liver disease that is caused by exposure to one of the five hepatitis viruses. Each virus is named after a letter of the alphabet, hepatitis A through E. Though other viruses can cause hepatitis, only the five are considered hepatitis viruses.

Each of the five hepatotropic viruses are alike in many ways. They all infect the cells of the liver causing inflammation. Depending on which virus is causing trouble, there is often an acute illness that produces similar signs and symptoms. However, to better understand the viruses requires knowing how they differ. Let's look at each one more closely.

Hepatitis A

Key Facts: People are usually exposed to hepatitis A by eating or drinking something contaminated with the virus. The infection is usually self-limited and may have a different effect on different people: children may have no symptoms whereas adults may have severe symptoms and be sick for up to two months. After the infection, people are immune from getting the disease again.

When someone is sick with hepatitis A, the person will pass the virus along in his or her stools. In developing countries with poor sanitation systems, infected stools can contaminate an entire water supply. In developed countries, like Australia, Japan, Western Europe, Canada and the United States, hepatitis A is most often spread by people who are infected with the virus but don't wash their hands well (or at all) after going to the toilet.

Good hygiene and avoiding contaminated food and water is a great defense, but the best protection is to get the hepatitis A vaccine -- which is especially recommended prior to traveling to places without a secure water supply.

Hepatitis B

Key Facts: Hepatitis B is a blood-borne disease that is usually spread several ways: through sexual contact, from a mother to her baby during childbirth, or through any direct contact with infected blood. As an acute disease, hepatitis B will go away in several months, but many people will become chronically infected, which increases the risk of developing other diseases. Two of the more serious diseases are cirrhosis and liver cancer. Chronic hepatitis B is treated with a combination of antiviral medications. The best strategy is to avoid infection in the first place by getting the hepatitis B vaccine.

Hepatitis C

Key Facts: Hepatitis C is a blood-borne disease that is spread through direct blood-to-blood contact. At least half of all new cases of hepatitis C are spread through sharing illicit drug needles or works. Hepatitis C can be spread by sexual contact but this is very rare. There is no vaccine for hepatitis C yet, so it is important to reduce the risk of infection by not coming into contact with infected blood and following simple rules of prevention. Though hepatitis C starts as an acute infection and may only last for a couple of months, most people will go on to have a chronic infection. This requires treatment with a combination of antiviral medications.

Hepatitis D

Key Facts: Hepatitis D is a unique virus that can only infect someone already infected with hepatitis B. For this reason, being vaccinated with hepatitis B vaccine will also protect against hepatitis D infection. It is a blood-borne virus and will develop either as a co-infection with hepatitis B, or a superinfection of hepatitis B. Either way, it will be treated along with the hepatitis B infection.

Hepatitis E

Key Facts: Essentially, hepatitis E is very similar to hepatitis A in the way it's spread and the type of disease it causes -- however, it is often more severe and can have more serious outcomes in pregnant women and their babies. Hepatitis E is very common in many developing countries and can spread to developed countries through normal travel and immigration. There is no vaccine available yet, but avoiding contaminated food and water, and practicing frequent handwashing are excellent ways to prevent infection. It is not spread from person-to-person.

Is There a Hepatitis G Virus?

Some older books and websites list additional hepatitis viruses. These are virus-like agents transmitted in blood that was once suspected of causing hepatitis but do not:

  • Hepatitis G
  • Transfusion transmitted virus (TTV)

Other Viruses that Cause Viral Hepatitis

A "hepatitis virus" is one of the five hepatotropic viruses, named A through E. However, there are other viruses and diseases that can cause hepatitis and symptoms similar to viral hepatitis, in addition to other infections. Three of many are:​​

  • Infectious mononucleosis
  • Cytomegalovirus (CMV)
  • Epstein-Barr virus
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Article Sources

  • Centers for Disease Control and Prevention. July 10, 2008. Viral Hepatitis.
  • Dienstag, JL. Acute Viral Hepatitis. In: AS Fauci, E Braunwald, DL Kasper, SL Hauser, DL Longo, JL Jameson, J Loscaizo (eds), Harrison’s Principles of Internal Medicine, 17e. New York, McGraw-Hill, 2008.