M/I: Infectious causes of hepatitis 1 and 2

Question 1

LO: understand the kinds of liver disease (acute and chronic) caused by viruses and the range of viruses that cause hepatitis
What are the different broad types of viral hepatitis?

Answer 1

Acute disease (wks to months, no chronic sequelae):
-non specific, flu-like symptoms
-jaundice, dark urine, pale faeces.
Chronic disease (years to lifetime)
-general malaise
-cirrholsis, liver cancer
Fulminant disease: Acute, precipitous infection

Question 2

LO: understand that five different viruses that cause hepatitis (HAV, HEV, HBV, HDV and HCV as their predominant presentation and their different epidemiology and sequelae.
How are the 5 viruses transmitted and prevented?

Answer 2

Hep A: faeces, faeco-oral. Pre/post exposure vaccination
Hep B: blood/blood-dervived body fluids, percutaneous/permucosal. Pre/post exp vac.
Hep C: B/BD BF, PC/PM. Blood donor screening, risk modification behavior.
Hep D: B/BD BF, PC/PM. Pre/post exp vac, risk behav mod
Hep E: faeces, faeco-oral route. Ensure safe drinking water.

Question 3

• understand the characteristics of HAV and HEV

Answer 3

m

Question 4

• understand the epidemiology of HAV and HEV

Answer 4

b

Question 5

• understand the features of their immune based pathogenesis

Answer 5

bb

Question 6

• understand the laboratory diagnosis of HAV and HEV

Answer 6

b

Question 7

• understand the current status of drugs and vaccines for HAV and HEV

Answer 7

b

Question 8

What are the signs/sequelae of viral hepatitis and what causes them?

Answer 8

It is the IMMUNE response (lymphocyte infiltration- pic) to viruses that causes the damage.
Jaundice (from hyperbilirubinemia)
Cirrhosis from chronic liver damage (pic- blistering of surface, loss of lobule architecture)
Hepatocellular carcinoma.

Question 9

Describe the pathogenesis of viral hepatitis

Answer 9

Hepatitis viruses are NOT cytolytic (replicate in but don’t lyse cells), thus most disease is immune mediated, thus you have AGE related outcomes.
Exposure early in life (less competent immune system) results in
-less severe acute disease
-higher rates of chronic infection

Question 10

What are the types of hepatitis viruses and is there cross protection between them?

Answer 10

Hep A (infectious hepatitis)
Hep B (serum hepatitis)
Hep C (serum non-A, non-B)
Hep D (dependent on HBV)
Hep E (enteric non-A, non-B)
NO they are from different families. 

Hep A and E cause acute disease
Hep B and C cause chronic disease so are the most significant (but Hep D also chronic..so..?)

Question 11

World distribution of Hep A?

Answer 11

High prevalence in low socio-economic countries e.g. Africa, Asia, South America

Question 12

What is the prevalence distribution of Hep A in Australia?

Answer 12

Now about equal in males/females (used to be higher in males).
Much higher incidence in Indigenous ppl

Question 13

What is the structure and classification of Hep AV?

Answer 13

Picornaviridae (small rna virus) family- Hepatovirus
Non enveloped + ssRNA virus, survive in water/stomach acid due to protein coat
Single serotype worldwide

Question 14

What is the life cycle of Hep AV?

Answer 14

Contaminated food/water is ingested
There is REPLICATION of virus in intestinal epithelial cells
Then viraemia (spread to blood)
Reaches liver, REPLICATION (get v high levels)
Exits in bile/faeces.