13.3: Pathology: Infectious causes of hepatitis 2 Flashcards
Which hepatitis viruses are chronic?
HBV, HCV, HDV
What is the prevalence of Hep infections in Australia?
Chronic hep: 18x more prevalent than HIV
What is the structure of HBV
Double walled, outer envelope and inner capsid
also has incomplete particles containing only envelope proteins-antibody decoy but not infectious
What type of virus is HepB? How does transcription start?
dsDNA: several RNA transcription start sites (using viral DNA polymerase to mend incomplete double strand) to make cccDNA
What is the core protein? What does it do?
HBeAg, adds the pre-C region
How does Hep B replicate?
RNA: reverse transcription, makes dsDNA genome of HBV virion (high error rate=mutants)
Where do the chronic hep viruses penetrate and replicate?
Penetrate mucosal epithelia, replicate in the liver
**What are the outcomes of HBV by age at infection?
The earlier the infection, the more likely to be a chronic but asymptomatic infection
If infected later (e.g. 4+yo.), chance of chronic infection is low but symptomatic infection likely
What is the serological course for HBV with recovery?
High anti-HBe indicates this person will recover
Low HBeAg
What is the serological course for HBV with progression to a chronic infection?
HBeAg: high
Anti-HBe: low
How do we determine a chronic carrier of HBV?
What is the sequelae?
HBsAg+
Cirrhosis, liver failure, primary hepatocellular carcinoma
What is the marker for HBV recovery or immunity/successful vaccination?
What indicates the virus is no longer replicating?
Anti-HBs Ig
Anti-HBe Ig
What can be used to treat HBV?
What can be used to prevent it?
3TC and Adefovir (nucleotide analogue)
Hep B vaccine (also against HDV)
How does HDV infect?
What is the difference between the two types of co-current infections?
Only in conjunction with HBV
Coinfection (severe acute disease, low risk of chronic)
Superinfection (HDV on top of HBV, chronic infection, high risk of severe liver disease)
Is the immune response to Hep C effective?
Is there a vaccine?
Yes, 30% of people clear it
No vaccine (high mutation rate and genotype diversity)
