Hepatitis can be categorized in two groups:

• acute hepatitis
• chronic hepatitis

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

• Hepatitis A (More about Hepatitis A)
  This type of hepatitis is usually spread by fecal-oral contact, or fecal-infected food and water, and 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 hand washing
  • 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 (More about Hepatitis B)
  Hepatitis B 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 full-blown liver failure and death. Transmission of hepatitis B virus occurs through blood and body fluid exposure such as blood, semen, vaginal secretions, or saliva. 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 a child has many scrapes or cuts. The following describes persons who are at risk for developing hepatitis B:
  • children born to mothers who have hepatitis B (the illness may present up to five 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
  • persons who live in long-term care facilities or who are disabled
  • persons who live in households where another member is infected with the virus
  • persons who have a blood clotting disorder such as hemophilia
  • persons who require dialysis for kidney failure
  • persons who may participate in high-risk activities such as intravenous (IV) drug use and/or unprotected heterosexual or homosexual sexual contact
  • persons who have a job that involves contact with human blood A vaccine for hepatitis B does exist and is now widely used for routine childhood immunization.
• Hepatitis C (More about 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 Centers for Disease Control and Prevention (CDC), hepatitis C is the leading indication for liver transplantation. With some cases of hepatitis C, no mode of transmission can be identified. In addition, people with alcoholic liver disease also tend to develop hepatitis C.

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

• children born to mothers who are infected with the virus
• persons who have a blood clotting disorder such as hemophilia and received clotting factors before 1987
• persons who require dialysis for kidney failure
• individuals who received a blood transfusion before 1992
• persons who may participate in high-risk activities such as intravenous ( IV) drug use and/or unprotected heterosexual or homosexual sexual contact

There is no vaccine for hepatitis C. Persons who are at risk should be checked regularly for hepatitis C. Persons who have hepatitis C should be monitored closely for signs of chronic hepatitis and liver failure.

• Hepatitis D
  This form of hepatitis can only occur 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 full-blown 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, individuals with clotting disorders such as hemophilia, and individuals who require hemodialysis for renal failure. Often, hepatitis G shows no clinical symptoms.