Hepatitis B virus

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Summary of Hepatitis B virus

Hepatitis B virus, abbreviated HBV, is a species of the Hepadnaviridae family of viruses. The genome of HBV is made of circular DNA, but it is unusual because the DNA is not fully double-stranded. HBV DNA polymerase has DNA- and RNA-dependent activities. Upon entry into nucleus, the polymerase completes the partial dsDNA. The main components of hepatitis B virus are hepatitis B surface antigen and core antigen. In addition to causing hepatitis, infection with HBV can lead to cirrhosis and hepatocellular carcinoma. Transmission is via parenteral or sexual contact.

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Hepatitis B virus

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NOTES NOTES HEPADNAVIRIDAE MICROBE OVERVIEW ▪ Hepadnaviridae: family of DNA viruses, causes liver disease ▪ Produces DNA polymerase with reverse transcriptase, RNAse activity Replication/multiplication ▪ Reverse transcription (RNA intermediate) Structure ▪ Enveloped ▪ Icosahedral capsid ▪ Partially double stranded, partially single stranded circular DNA COMPLICATIONS ▪ Chronic hepatitis, acute liver failure (fulminant hepatitis), liver cirrhosis, hepatocellular carcinoma (HCC) HEPATITIS B VIRUS osms.it/hepatitis-b-virus PATHOLOGY & CAUSES ▪ Hepatitis B virus (HBV) ▫ DNA virus: can cause acute/chronic liver disease ▫ Member of Hepadnaviridae family (only human pathogenic species) ▪ Target: hepatocytes, zone I (periportal area) ▪ Incubation period: six weeks to six months Antigens ▪ Hepatitis B surface antigen (HBsAg/ Australia antigen) ▫ Key infection marker ▪ Hepatitis B core antigen (HBcAg) ▫ Not detectable in serum; found in liver with acute/chronic hepatitis B ▪ Hepatitis B e antigen (HBeAg) ▫ Secreted by infected cells; indicates active infection, replication Transmission ▪ Perinatal (childbirth), parenteral (e.g. IV drug use, blood transfusions), sexual ▪ HBV survives ≥ seven days in environment Highest prevalence ▪ Parts of sub-Saharan Africa, mainly due to perinatal transmission ▪ Lower prevalence areas have greater association with parenteral, sexual transmission TYPES Acute hepatitis ▪ Liver inﬂammation for < six months) ▪ HBV penetrates hepatocytes → CD8+ T-lymphocyte activation → cytotoxic killing → hepatocyte apoptosis → liver damage, inﬂammation ▪ Phases ▫ Early, window (antigens undetectable), recovery OSMOSIS.ORG 417

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Hepatitis B virus

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A 42-year-old man presents to an outpatient clinic due to concerns for contracting a sexually transmitted infection. He reports that several months ago, he had unprotected sexual intercourse, and several weeks thereafter, he experienced malaise, fatigue, and jaundice. He reports since then, his symptoms have abated, but he is concerned because he started a new relationship and does not want to “potentially infect” his new partner. Laboratory findings are demonstrated below:

Which of the following best describes the current clinical stage of this patient?

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