Hepatitis B

Posted by e-Medical PPT Saturday, July 16, 2011
HBV, small double stranded DNA virusHepadnaviridae
Infection restricted to humans and higher apes
High levels in blood (102 to 1010 copies/ml)
Causes both acute and chronic hepatitis
Parenteral, sexual and maternal-infant spread
Marked geographic variation in incidence
Common in Asia and Africa, uncommon in the United States and Western Europe

Hepatitis B Viral Genome
Circular, partially doubled-stranded DNA 
Four open reading frames
HBsAg (pre-S1, pre-S2 and S)
HBcAg (pre-core and core)
Polymerase (multifunctional)
HBxAg (transactivating factor)
Replicates largely in liver
Through RNA intermediate and reverse transcription

Chronic Hepatitis B: Three Clinical Forms:
HBeAg Positive Chronic Hepatitis B 
    HBeAg, raised ALT, HBV DNA in serum and chronic hepatitis on biopsy
HBeAg Negative Chronic Hepatitis B  
    Anti-HBe, raised ALT and HBV DNA in serum, chronic hepatitis on biopsy
Inactive HBsAg Carrier State 
    Anti-HBe, normal ALTand; no HBV DNA, minimal nonspecific changes on biopsy

Chronic Hepatitis B Long-Term Complications
Hepatocellular carcinoma
Polyarteritis Nodosa

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