HBV_High_Yield_Flashcards
What is the family and genome type of Hepatitis B Virus (HBV)?
Family: Hepadnaviridae. Genome: Circular double-stranded DNA (3.2 kb).
What is the structure of HBV?
Enveloped virus with icosahedral shape, contains DNA polymerase with reverse transcriptase activity.
What are the key antigens of HBV and their clinical importance?
HBsAg: Indicates acute or chronic infection. HBeAg: High infectivity. HBcAg: Found only in hepatocyte nuclei.
What does HBsAg (surface antigen) indicate?
HBsAg indicates acute infection. If present for >6 months, it suggests chronicity.
What does HBeAg (envelope antigen) indicate?
HBeAg is a marker of high infectivity and active replication.
What does HBcAg (core antigen) indicate?
HBcAg is found only inside hepatocyte nuclei and is not detectable in blood.
What does HBcAb IgM indicate?
HBcAb IgM indicates acute infection.
What does HBcAb IgG indicate?
HBcAb IgG indicates past or chronic infection.
What does HBeAb indicate?
HBeAb suggests low infectivity and reduced viral replication.
What does HBsAb indicate?
HBsAb indicates immunity (recovery or vaccination).
What is the ‘window period’ in HBV infection?
During the window period, HBsAg and HBsAb are undetectable; only HBeAb & IgM is present.
What are the modes of transmission for HBV?
Blood and body fluids, sexual transmission, vertical transmission (mother to fetus), needle sharing, inadequate sterilization.
What is the standard treatment for HBV?
Pegylated interferon for 6–12 months, especially in HBeAg-positive patients.
Which antiviral drugs are used for HBV?
Lamivudine, Adefovir, Telbivudine.
What is the vaccination schedule for HBV?
Recombinant DNA vaccine given at birth, 2, 4, and 6 months; high-risk groups receive 3 doses.
What measures are used to prevent vertical transmission of HBV?
Administer HBIG (specific immunoglobulin) to neonates born to HBV-positive mothers, followed by vaccination.
What percentage of HBV cases progress to mild symptoms, jaundice, or chronicity?
70% develop mild symptoms, 25% develop jaundice, and 5% progress to chronic hepatitis.
What diagnostic tests are used for HBV?
ELISA detects antigens (HBsAg, HBeAg) and antibodies (HBcAb, HBsAb).
What is the role of PCR in HBV diagnosis?
PCR detects HBV DNA and confirms active replication.
How stable is HBV in the environment?
Stable at -20°C for over 20 years, at 25°C for 1 week, and at 37°C for 60 minutes.
How can HBV be inactivated?
Inactivated by boiling (100°C for 1 minute), sodium hypochlorite (0.5%), or heat at 60°C for 10 hours.
What are the main phases of HBV infection markers?
Acute phase: HBsAg, HBeAg, and HBcAb IgM are present. Chronicity: HBsAg and HBcAb IgG remain.
