Viral hepatitis is inflammation of the liver caused by a virus. Several different viruses, named the hepatitis A, B, C, D, and E viruses, cause viral hepatitis.
All of these viruses cause acute, or short-term, viral hepatitis. The hepatitis B, C, and D viruses can also cause chronic hepatitis, in which the infection is prolonged, sometimes lifelong. Chronic hepatitis can lead to cirrhosis, liver failure, and liver cancer.
Researchers are looking for other viruses that may cause hepatitis, but none have been identified with certainty. Other viruses that less often affect the liver include cytomegalovirus; Epstein-Barr virus, also called infectious mononucleosis; herpesvirus; parvovirus; and adenovirus.
Symptoms include:
However, some people do not have symptoms.
Hepatitis A is spread primarily through food or water contaminated by feces from an infected person. Rarely, it spreads through contact with infected blood.
People most likely to get hepatitis A are:
The hepatitis A vaccine offers immunity to adults and children older than age 1. The Centers for Disease Control and Prevention recommends routine hepatitis A vaccination for children aged 12 to 23 months and for adults who are at high risk for infection. Treatment with immune globulin can provide short-term immunity to hepatitis A when given before exposure or within 2 weeks of exposure to the virus. Avoiding tap water when traveling internationally and practicing good hygiene and sanitation also help prevent hepatitis A.
Hepatitis A usually resolves on its own over several weeks.
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Hepatitis B is spread through contact with infected blood, through sex with an infected person, and from mother to child during childbirth, whether the delivery is vaginal or via cesarean section.
People most likely to get hepatitis B are:
The hepatitis B vaccine offers the best protection. All infants and unvaccinated children, adolescents, and at-risk adults should be vaccinated. For people who have not been vaccinated, reducing exposure to the virus can help prevent hepatitis B. Reducing exposure means using latex condoms, which may lower the risk of transmission; not sharing drug needles; and not sharing personal items such as toothbrushes, razors, and nail clippers with an infected person.
Drugs approved for the treatment of chronic hepatitis B include alpha interferon and peginterferon, which slow the replication of the virus in the body and also boost the immune system, and the antiviral drugs lamivudine, adefovir dipivoxil, entecavir, and telbivudine. Other drugs are also being evaluated. Infants born to infected mothers should receive hepatitis B immune globulin and the hepatitis B vaccine within 12 hours of birth to help prevent infection.
People who develop acute hepatitis B are generally not treated with antiviral drugs because, depending on their age at infection, the disease often resolves on its own. Infected newborns are most likely to progress to chronic hepatitis B, but by young adulthood, most people with acute infection recover spontaneously. Severe acute hepatitis B can be treated with an antiviral drug such as lamivudine.
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Hepatitis C is spread primarily through contact with infected blood. Less commonly, it can spread through sexual contact and childbirth.
People most likely to be exposed to the hepatitis C virus are:
There is no vaccine for hepatitis C. The only way to prevent the disease is to reduce the risk of exposure to the virus. Reducing exposure means avoiding behaviors like sharing drug needles or personal items such as toothbrushes, razors, and nail clippers with an infected person.
Chronic hepatitis C is treated with peginterferon together with the antiviral drug ribavirin.
If acute hepatitis C does not resolve on its own within 2 to 3 months, drug treatment is recommended.
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Hepatitis D is spread through contact with infected blood. This disease only occurs at the same time as infection with hepatitis B or in people who are already infected with hepatitis B.
Anyone infected with hepatitis B is at risk for hepatitis D. Injection drug users have the highest risk. Others at risk include:
People not already infected with hepatitis B should receive the hepatitis B vaccine. Other preventive measures include avoiding exposure to infected blood, contaminated needles, and an infected person’s personal items such as toothbrushes, razors, and nail clippers.
Chronic hepatitis D is usually treated with pegylated interferon, although other potential treatments are under study.
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Hepatitis E is spread through food or water contaminated by feces from an infected person. This disease is uncommon in the United States.
People most likely to be exposed to the hepatitis E virus are:
There is no U.S. Food and Drug Administration (FDA)-approved vaccine for hepatitis E. The only way to prevent the disease is to reduce the risk of exposure to the virus. Reducing risk of exposure means avoiding tap water when traveling internationally and practicing good hygiene and sanitation.
Hepatitis E usually resolves on its own over several weeks to months.
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Some cases of viral hepatitis cannot be attributed to the hepatitis A, B, C, D, or E viruses, or even the less common viruses that can infect the liver, such as cytomegalovirus, Epstein-Barr virus, herpesvirus, parvovirus, and adenovirus. These cases are called non-A–E hepatitis. Scientists continue to study the causes of non-A–E hepatitis.
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The National Institute of Diabetes and Digestive and Kidney Diseases, through its Division of Digestive Diseases and Nutrition, supports basic and clinical research into the nature and transmission of the hepatitis viruses, and the activation and mechanisms of the immune system. Results from these basic and clinical studies are used in developing new treatments and methods of prevention.
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American Liver Foundation
75 Maiden Lane, Suite 603
New York, NY 10038–4810
Phone: 1–800–GO–LIVER (465–4837), 1–888–4HEP–USA (443–7872), or 212–668–1000
Fax: 212–483–8179
Email: info@liverfoundation.org
Internet: www.liverfoundation.org
Centers for Disease Control and Prevention
Division of Viral Hepatitis
1600 Clifton Road
Mail Stop C–14
Atlanta, GA 30333
Phone: 1–800–CDC–INFO (232–4636)
Fax: 404–371–5488
Email: cdcinfo@cdc.gov
Internet: www.cdc.gov/hepatitis
Hepatitis Foundation International
504 Blick Drive
Silver Spring, MD 20904–2901
Phone: 1–800–891–0707 or 301–622–4200
Fax: 301–622–4702
Email: hfi@comcast.net
Internet: www.hepatitisfoundation.org