Hepatitis B virus is an hepadnavirus—hepa from hepatotrophic and dna because it is a DNA virus—and it has a circular genome composed of partially double-stranded DNA. The viruses replicate through an RNA intermediate form by reverse transcription, and in this respect they are similar to retroviruses. The three main antigens: - HbsAg ---> Hepatitis B Surface Antigen - HbcAg ---> Hepatitis B Core Antigen - HbeAg ---> Hepatitis B Envelope Antigen Serology: Early in an infection, HBsAg may not be present. During this ‘window’ in which the host remains infected but is successfully clearing the virus, anti-HBc IgM may be the only serological evidence of disease. Therefore most hepatitis B diagnostic panels contain HBsAg and total anti-HBc (both IgM and IgG). Shortly after the appearance of the HBsAg, HBeAg will appear. HBeAg may be cleared, and anti-HBe will arise immediately afterwards. This conversion is usually associated with a dramatic decline in viral replication. Eventually the HBsAg will become undetectable and will be followed by anti-HBs and anti-HBc IgG. Individuals who remain HBsAg positive for at least six months are considered to be hepatitis B carriers.
Posted on: Fri, 05 Sep 2014 08:24:53 +0000
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