Approximately how many people worldwide have been infected with HBV?
~2 billion people globally, with >240 million chronic infections.
What are the main transmission routes of hepatitis B virus?
Percutaneous, sexual, and perinatal transmission (vertical).
What geographic regions have the highest prevalence of chronic HBV?
East Asia, Pacific Islands, and sub-Saharan Africa.
What type of genome does hepatitis B virus contain?
Partially double-stranded DNA.
How does HBV replicate despite being a DNA virus?
Replication via reverse transcription through an RNA intermediate.
Risk factors for HCV
Migrants from endemic regions
Family/ parents of infectes patients
Healthcare workers
Drug users (injected)
Living in closed settings
High risk sexual practices
People with HIV
What is the HBsAg protein?
Surface protein used to diagnose infection
What is the HBcAg protein?
Core protein inside the virus that activates the immune response
What is the HBeAg protein?
Protein that indicates active rapid replication
Protein associated with liver cancer that helps the virus control the cell
X protein
What causes liver injury in hepatitis B infection?
Immune-mediated destruction of infected hepatocytes by CD8+ cytotoxic T cells targeting HBcAg-associated complexes.
Who usually acute develops infection?
Adults
Who usually develops chronic infection?
Children
Why do neonates frequently develop chronic HBV infection?
The virus has immune tolerance due to an immature immune system with weak cytotoxic T-cell response.
What determines whether HBV infection resolves or becomes chronic?
Balance between viral replication and host immune response.
What is the primary marker of HBV infection?
HBsAg in serum.
What does IgM anti-HBc indicate?
Recent HBV infection (within ~6 months) or reactivation.
What does HBeAg indicate?
High viral replication and increased infectivity.
What does anti-HBe signify?
Reduced viral replication and decreased infectivity.
What does anti-HBs indicate?
Protective immunity to HBV.
What serology pattern indicates vaccination?
Isolated anti-HBs positivity.
What serology pattern indicates resolved HBV infection?
Anti-HBs + anti-HBc + anti-HBe.
What major malignancy is strongly associated with chronic HBV infection?
Hepatocellular carcinoma (HCC).
What viral mechanism contributes to HBV-associated hepatocellular carcinoma?
Integration of HBV DNA into the host genome.
