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ABCs of Hepatitis
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What Is Hepatitis B?
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Hepatitis B is a liver disease caused by the hepatitis B virus (HBV).
Hepatitis B is a form of viral hepatitis that is also known as serum hepatitis, due to its ability to be spread through body fluids and blood. HBV can cause lifelong infection, cirrhosis (scarring) of the liver, liver cancer, liver failure, and death. Hepatitis B is a more severe liver disease than hepatitis A, and asymptomatic infections occur frequently. Chronic hepatitis B infection may take one of two forms: chronic persistent hepatitis, a condition characterized by persistence of the virus but in which liver damage is minimal; and chronic active hepatitis, in which there is aggressive destruction of liver tissue and rapid progression to cirrhosis or liver failure.
Transmission of HBV occurs through blood and body fluid exposure such as blood, semen, vaginal secretions, or saliva. Hepatitis B is not spread through food or water or by casual contact. 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 common modes of transmission of hepatitis B are as follows:
Worldwide there are 450 million carriers of hepatitis B, 50 million of which are in Africa. Carriage rates vary markedly in different areas. In South Africa, infection is much more common in rural communities than in the cities.
According to the Centers for Disease Control (CDC), an estimated 78,000 persons in the United States were infected with HBV in 2001. People of all ages get hepatitis B, and about 5,000 die per year of sickness caused by HBV. An estimated 1.25 million Americans are chronically infected, of whom 20 to 30 percent acquired their infection in childhood. It is estimated that hepatitis B accounts for 20 to 25 percent of all acute viral hepatitis in children. Infected newborns rarely suffer but have 90 percent chance of becoming carriers. Twenty-five percent of all HAV positive newborns develop chronic liver disease by the third to fourth decade of life.
Hepatitis B is caused by HBV, also called Hepadna virus. The virus has an incubation period of two to five months. It replicates in the liver, and virus particles are shed in large amounts into the blood. The blood of infected individuals is thus highly infectious.
Hepatitis B has a wide range of symptoms. It can also be mild, without symptoms. When present, the symptoms are non-specific and usually include fever, tiredness, loss of appetite, nausea, abdominal discomfort, dark urine, clay-colored bowel movements, and jaundice (yellowing of the skin and eyes).
Parents should call the doctor immediately if any of the following occurs:
A blood test is required to diagnose hepatitis B. The test detects one of the viral antigens called hepatitis B surface antigen (HBsAg) in the blood. Later on, HBsAg may no longer be present, in which case a test for antibodies to a different antigen, called hepatitis B core antigen, is used. If HBsAg can be detected in the blood for longer than six months, chronic hepatitis B is diagnosed.
There is no cure for hepatitis B and no specific treatment is available. However, the following guidelines are often recommended:
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Author Info: Monique Laberge Ph.D., Thomson Gale, Gale, Detroit, Gale Encyclopedia of Children's Health, 2006 |