Hepatitis B overview: Difference between revisions
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The hepatitis B virus is responsible for causing hepatitis B. HBV is a | The hepatitis B virus is responsible for causing hepatitis B. HBV is a double stranded DNA virus belonging to the family Hepadnaviridae. The viral particle consists of an outer lipid envelope and an icosahedral nucleocapsid core composed of protein. The nucleocapsid encloses the viral DNA. HBV DNA polymerase has reverse transcriptase activity. It shows tropism for hepatocytes. Humans are the only natural reservoir. | ||
==Differentiating Hepatitis B from other Diseases== | ==Differentiating Hepatitis B from other Diseases== | ||
Revision as of 04:05, 4 August 2014
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Hepatitis B |
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Diagnosis |
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Treatment |
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Case Studies |
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Hepatitis B overview On the Web |
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American Roentgen Ray Society Images of Hepatitis B overview |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Jolanta Marszalek, M.D. [2]; João André Alves Silva, M.D. [3]
Overview
Hepatitis B virus(HBV) is a double stranded DNA virus belonging to the family Hepadnaviridae. It is responsible for hepatitis B virus infection in humans that attacks the liver and causes both acute and chronic disease.
Historical Perspective
The earliest record of an epidemic caused by HBV was made by Lurman in 1885 after an outbreak of smallpox led to the vaccintation of shipyard employees with prepared material from human lymph. Several weeks to 8 months later, some of the workers became ill with jaundice while unvaccinated workers remained healthy. Similar outbreaks of serum hepatitis were reported throughout the early 20th century in clinics treating diabetes, syphilis, and tuberculosis. These outbreaks were most likely due to the transmission of the virus through the the use of contaminated needles and syringes. During World War II, jaundice epidemics occurring amongst military personnel led to studies that differentiated hepatitis B from hepatitis A. The virus itself was not discovered until 1965 by Baruch Blumberg, who identified the Australia antigen(later known to be hepatitis B surface antigen or HBsAg) in blood collected from Australian aborigines. The virus particle was identified in 1970 with electron microscopy by D.S. Dane et al. By the early 1980's the virus' genome had been sequenced, and in 1982, a vaccine against HBV was available.
Pathophysiology
Hepatitis B virus is a non-cytopathic, intracellular virus that causes little or no damage to the cell.[1] The host immune response to the virus is responsible for the hepatocellular damage seen in HBV infection. The HBV virion binds to a receptor at the surface of the hepatocyte and enters the cell, where it uses the host's cell mechanisms to replicate its genome and proteins.[1] The following viral antigens and antibodies are detected in serum throughout the course of the disease: HBsAg, HBcAg, HBeAg, anti-HBs, anti-HBC and anti-HBe. Transmission occurs from exposure to infectious blood or body fluids. Immune complexes, such as surface antigen-antibody, are important in the pathogenesis of hepatitis B. Hepatitis B is associated with the development of hepatocellular carcinoma.
Causes
The hepatitis B virus is responsible for causing hepatitis B. HBV is a double stranded DNA virus belonging to the family Hepadnaviridae. The viral particle consists of an outer lipid envelope and an icosahedral nucleocapsid core composed of protein. The nucleocapsid encloses the viral DNA. HBV DNA polymerase has reverse transcriptase activity. It shows tropism for hepatocytes. Humans are the only natural reservoir.
Differentiating Hepatitis B from other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Treatment
Surgery
The treatment of hepatitis B usually involves no surgical procedures. However, among patients with advanced liver damage secondary to HBV infection or liver failure in fulminant hepatitis, liver transplantation may be beneficial.
References
- ↑ 1.0 1.1 "Hepatitis B" (PDF).