Hepatitis B and D

Question 1

Transmission of Hep B

Answer 1

• blood
• sex
• mother to child (vertical)

Question 2

HBV replication

Answer 2

1. DNA replication usign viral and host enzymes
2. manufacture the viral proteins (surface, core, polymerase, e-antigen) using host ribosomes
3. excess surface antigen and e antigen secreted into circulation without genetic material (detectable in blood)
4. proteins assembled together to make virus
5. virus secreted from cell into circulation

Question 3

HBV DNA replication

Answer 3

DNA –> RNA (host enzyme)
RNA –> DNA (reverse transcriptase)
This process also occurs in HIV - can attack virus with the same drugs

Question 4

How does HBV cause liver damage

Answer 4

HBV cause immune response.

1. Viral proteins displayed on host MHC molecules.
2. T cells recognise viral proteins –>
3. apoptosis of infected cells and recruitment of B cells which make antibodies to HBV –> neutralisation

Question 5

HBV treatment

Answer 5

oral antiviral therapy

• tenovir / entecavir - nucleosides that prevent replication of viral DNA
• they reduce the serum viral titre –> reduced inflammation –> reduce progression

Question 6

Hep D

Answer 6

HDV infection requires HBV co-infection. HDV supresses HBV and causes liver damage (treating the Hep B won’t solve the problem).
Some cases of HDV respond to interferon