Hepatitis B

Question 1

What is Hepatitis B?

What pathogen causes Hepatitis B?

Answer 1

Viral infection of liver cells caused by Hepatitis B Virus

Question 2

How is Hepatitis B transmitted?

Answer 2

By exposure to infected blood or genital secretions.

Mother to child at moment of birth through birth canal.

Question 3

How does HBV exposure at birth differ from HBV exposure in adulthood?

Answer 3

When exposed to HBV at birth, baby will recognise HBV antigens as self and so will only develop a minimal immune response if any to the virus.

When exposed to HBV as an adult, the immune system will fight it like any other infection and have a greater chance of eradicating it before it becomes chronic.

Question 4

How does liver damage occur in Hepatitis B?

How does this occur in chronic Hepatitis B acquired at birth?

Answer 4

Cytotoxic T cells target abnormal, virus producing liver cells causing damage to liver cells.

When Hepatitis B is acquired at birth the damage occurs slowly over the person’s lifetime, resulting in gradual liver cirrhosis.

Question 5

What are some symptoms of Hepatits B?

Answer 5

• Fever
• Pain
• Loss of appetite
• Jaundice with severe liver damage

Question 6

What Hepatitis B Virus proteins are produced by liver cells and can be detected in the blood?

Answer 6

Hepatitis B surface Antigen (HBsAg) and Hepatitis B e Antigen (HBeAg)

Question 7

What tests can confirm the presence of Hepatitis B in the blood?

Answer 7

PCR test of blood for viral DNA

ELISA Hepatitis B surface Antigen test (HBsAg)
- +ve = detectable in blood and infectious
- -ve = not detectable in blood and not infectious

Question 8

What test can determine the infectivity risk of an HBV positive person?

Answer 8

Hepatitis B e Antigen (HBeAg)
- +ve = High levels of virus, high risk of transmission
90% at birth
30% with needlestick
- -ve = Low levels of virus in blood, lower risk of transmission
10% at birth
3% with needlestick

Question 9

What tests can determine the extent of liver damage?

Answer 9

Blood tests for liver enzyme
- high levels = liver damage

Liver biopsy to measure inflammation

Question 10

What is the treatment for Hepatitis B?

Answer 10

Treat HBV infection
- Drugs can block HBV replication but won’t entirely get rid of HBV
- Undetectable in blood = Non transmissable

Advise against liver damaging habits e.g. alcohol consumption

Injection of isolated HBV antibodies into newborns to opsonise virus and prevent attachment to liver cells

Vaccination of HBsAg