Hepadnaviridae (hepa =liver, dna= deoxyribonucleic acid) GROUP VII
As the name indicates, Hepadnaviridae are a family of viruses that cause infections to the liver of human and animals and all cause hepatitis in their known host. Hepatitis is an inflammation of the liver. However, not all type of hepatitis is caused by Hepadnavirus family as it can be caused by other viruses or non-infectious agent such as alcohol.

Family of hepadnaviridae:
Genus: Orthohepadnavirus consist of virus such as:
· Hepatitis B (HBV)
· Ground squirrel Hepatitis virus
· Woodchuck hepatitis virus
Genus: Avihepadnavirus consist of virus such as:
· Duck Hepatitis B
· Heron Hepatitis B

Viral genome of hepadnaviridae (enveloped DNA virus)

The core contains:

• Circular, partially dsDNA
• DNA polymerase
• an antigen (HBcAg)
• contain overlapping open reading frames.
• since it is a group VII virus, replication involves an RNA intermediate.

Pathogenesis

• Causes persistent infection, can be chronic or acute.
• Acute or chronic depends on age of infection
• About 90% of adults infected with HBV recover from it completely& become immune to it.
• Other 10% are those who become chronic carriers.
• Babies given birth by infected mother have a high risk of becoming a chronic carrier.
  Interesting fact: do you know that hepatitis B virus is 50 to 100 more time more infectious than HIV.

Symptoms of acute Hepatitis B

• Can last for several weeks
• Yellowing of skin & eyes (jaundice)
• Extreme fatigue
• Nausea, vomiting and abdominal pain

Chronic hepatitis B
As I mention before, chronic Hepatitis B virus depends upon the age at which the person is infected.

• young children who are infected, are most likely to develop chronic infection.
• A chronic carrier has no symptoms and no abnormalities on laboratory test however they are still potentially infectious.
• around 90% of infants infected during the first year of life develop chronic infection.
• about 25% of chronically infected adult who are infected during childhood, die from HBV-related liver cancer or cirrhosis.