Viral Hepatitis Overview

What is hepatitis?

Hepatitis is inflammation of the liver that results in liver cell damage and destruction.

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Hepatitis can be categorized in two groups:

• Acute hepatitis
• Chronic hepatitis

There are six main types of the hepatitis virus that have been identified:

• Hepatitis A. This type of hepatitis is usually spread by fecal-oral contact, or fecal-infected food and water. It may also be spread by blood-borne infection (which is rare). The following is a list of modes of transmission for hepatitis A:
  • Consuming food made by someone who touched infected feces
  • Drinking water that is contaminated by infected feces (a problem in developing countries with poor sewage removal)
  • Touching an infected person's feces, which may occur with poor handwashing
  • Outbreaks may occur in large childcare centers, especially when there are children in diapers
  • Residents of American Indian reservations or Native Alaskan villages where hepatitis A may be more common
  • Sexual contact with an infected person
  A vaccine for hepatitis A has been developed and is now available.
• Hepatitis B. Hepatitis B (HBV) has a wide range of clinical presentations. It can be mild, without symptoms, or it may cause chronic hepatitis and, in some cases, can lead to liver failure and death. Transmission of hepatitis B virus occurs through body fluid exposure, such as blood, semen, vaginal secretions, or saliva. Needle sticks, sharp instruments, sharing items (razors, toothbrushes) and sex with an infected person are primary modes of transmission. Infants may also develop the disease if they are born to a mother who has the virus. Infected children often spread the virus to other children if there is frequent contact, or if a child has many scrapes or cuts. The following describes people who are at risk for developing hepatitis B:
  • Children born to mothers who have hepatitis B (the illness may present up to 5 years after the child is born)
  • Children who are born to mothers who have immigrated from a country where hepatitis B is widespread, such as southeast Asia and China
  • People who live in long-term care facilities or who are disabled
  • People who live in households where another member is infected with the virus
  • People who have a blood clotting disorder such as hemophilia
  • People who need dialysis for kidney failure
  • People who participate in high-risk activities such as intravenous (IV) drug use and/or unprotected heterosexual or homosexual sexual contact
  • People who have jobs that involve contact with human blood
  • People who received blood transfusions or blood products before the early 1990s

  A vaccine for hepatitis B does exist and is now widely used for routine childhood immunization. The Centers for Disease Control and Prevention (CDC) now recommends that universal infant hepatitis B vaccination should begin at birth, except in rare circumstances.

• Hepatitis C. The symptoms of hepatitis C are usually mild and gradual. Children often show no symptoms at all. Transmission of hepatitis C occurs primarily from contact with infected blood, but can also occur from sexual contact, or from an infected mother to her baby. Although hepatitis C has milder symptoms initially, it leads to chronic liver disease in a majority of people who are infected. According to the CDC, hepatitis C is the leading indication for liver transplantation. With some cases of hepatitis C, no mode of transmission can be identified. 
  

  The following describes people who may be at risk for contracting hepatitis C:

  • Children born to mothers who are infected with the virus
  • People who have a blood clotting disorder such as hemophilia and received clotting factors before 1987
  • People who need dialysis for kidney failure
  • Individuals who received a blood transfusion before 1992
  • People who participate in high-risk activities such as intravenous drug use and/or unprotected heterosexual or homosexual sexual contact
  There is no vaccine for hepatitis C. People who are at risk should be checked regularly for hepatitis C. People who have hepatitis C should be monitored closely for signs of chronic hepatitis and liver failure.
• Hepatitis D. This form of hepatitis can occur only in the presence of hepatitis B. If an individual has hepatitis B and does not show symptoms, or shows very mild symptoms, infection with D can put that person at risk for liver failure that progresses rapidly. Hepatitis D can occur at the same time as the initial infection with B, or it may show up much later. Transmission of hepatitis D occurs the same way as hepatitis B, except the transmission from mother to baby is less common.
• Hepatitis E. This form of hepatitis is similar to hepatitis A. Transmission occurs through fecal-oral contamination. It is less common than hepatitis A. Hepatitis E is most common in poorly-developed countries and rarely seen in the United States. There is no vaccine for hepatitis E at this time.
• Hepatitis G. This is the newest strain of hepatitis and very little is known about it. Transmission is believed to occur through blood and is most commonly seen in IV drug users, people with clotting disorders, such as hemophilia, and people who need hemodialysis for renal failure. Often, hepatitis G shows no clinical symptoms and has not been found to be a cause of acute or chronic hepatitis.

How often does hepatitis occur?

According to the CDC, in the United States:

• Hepatitis A rates have declined by 92 percent since the hepatitis A vaccine first became available in 1995.
• An estimated 800,000 to 1.4 million people have chronic hepatitis B infections.
• An estimated 3.2 million people have hepatitis C infections. 

Preventing the spread of viral hepatitis

Proper hygiene is the key to preventing the spread of many diseases, including hepatitis. Other preventive measures include the following:

• Vaccinations. A hepatitis B vaccine is routinely given to toddlers as part of their immunization schedule. A hepatitis A vaccine is available for people at risk. (There are no vaccines for hepatitis C, D, E, or G at this time.)
• Blood transfusion. Blood for transfusions is routinely screened for hepatitis B and C to reduce the risk of infection.
• Antibody preparation. If a person has been exposed to hepatitis, an antibody preparation can be given to help protect them from the disease.

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