Hepatitic B/C

Question 1

How is Hep C transmitted?

Answer 1

Percutaneous;
Injecting drug use
Therapeutic (contamination)
Transfusion/Transplantation.
Vertical transmission

Question 2

Precentages! (Hep C) Acute>Chronic>Cirrhosis>Carcinoma

Answer 2

Acute80%>Chronic20%>Cirrhosis1-4%>Carcinoma (hepatocellular).

Question 3

Timeframe and factors influencing progression of Hep C to cirrhosis?

Answer 3

20 years, made shorter by alcohol and co-infection (HIV, Hep B), made longer by being female and younger.

Question 4

Genome of Hep C?

Answer 4

(+)ssRNA forming one polyprotein, large variation (6 Genotypes), no enzymes carried, replicated by RNAdepRNApol produced in the cell.

Question 5

Where does Hep C replicate?

Answer 5

ONLY in the cytoplasm.

Question 6

Factors influencing Hep C infectivity. (4)

Answer 6

1. High replication rate
2. Altering T cell function, blocking innate immunity.
3. Proteins alter metabolism (->Steatosis, inlammation, cancer)
4. No proof reading leads to mutations and evasion of immunity.

Question 7

Therapy for Hep C?

Answer 7

Interferon. Direct acting antivirals (Directly target virion). New drugs target protease, polymerase. However resistance will emerge, therefore combined treatments preferred.
NO VACCINE

Question 8

Hep. B transmission?

Answer 8

Transfusion, IV drug use, tattoos, acupuncture, therapeutic (contamination) sexual, vertical, Coinfection increases risk.

Question 9

Percentage of Hep B progressing to chronic infection?

Answer 9

ADULTS: 3-5%. CHILDREN: - 70-95% (due to undeveloped immune system.)

Question 10

Characteristics of Hep B infection?

Answer 10

Long incubation (14-90 days), 95% of hepatocytes effected, immune clearance determines acute or chronic infection.

Question 11

Fate of Hep B genome?

Answer 11

Converted from rcDNA to cccDNA in nucleus, RNA is produced, packaged back into nucleocapsids and can either re-enter the nucleus or bud to produce new virions.

Question 12

Particles of Hep B infection?

Answer 12

Virions, Secreted filaments, secreted spheres.

Question 13

Treatment of Hep B?

Answer 13

VACCINE! small envelope protein is absorbed onto aluminium hydroxide (Adjuvant). Antiviral therapy does not target cccDNA but blocks polymerase, however because cccDNA is not targeted, removal of AVT causes virus to rebound.

Question 14

New Hep C medication?

Answer 14

Teleprivir/Boceprivir blocks NS34A Protease, preventing cleavage of the polyprotein.

Question 15

Risk of Cancer with Hep B?

Answer 15

25% of chronically infected patients develop primary hepatocellular carcinoma. (lifetime risk)

Question 16

Proteins produced by hep B? (4)

Answer 16

Polymerase, surface proteins, Core proteins, X protein.

Question 17

Virus factors in Hep B infection maintenance?

Answer 17

Stability of genome (DNA + histones = mini chromosome), AV does not target cccDNA, high mutation rate.