Microbiology: Hepatitis Viruses 3

Question 1

What are the microbiological characteristics of HCV?

Answer 1

ssRNA+ enveloped isosahedral capsid
6 major genotypes
Encodes polyprotein cleaved by NS3 protease

Question 2

What are the epidemiological characteristics of HCV?

Answer 2

Untreated become chronic carriers
45-55 yo men
Hospital workers, hemophiliacs, HIV infected
Drug users dialysis
Alcoholic liver disease

Question 3

What is the typical time table for HCV infection?

Answer 3

Chronic (10yrs) –> Cirrhosis (20yrs) –> HCC (30yrs)

Question 4

What is the pathogenesis of HCV infection?

Answer 4

Parenterally spread –> replicates in liver (7-9 weeks) –> causes immune mediated destruction –> Hepatitis, cirrhosis, Liver failure, Liver transplant

Question 5

What are the most common methods of transmission?

Answer 5

IV drug abuse > Sexual transmission > blood transfusions

Question 6

What is the clinical presentation of HCV infection?

Answer 6

Same as other hepatitis infections

Can be recurrent due to immune escape via HVR1 near E2 gene

Question 7

How is HCV diagnosed?

Answer 7

Screen for HCV core antigen
Get RNA for RT-PCR to determine Genotype

Screening test of choice:
HepC Antibody —> HCV RNA PCR —> Biopsy (***Biopsy is to determine severity!)

Question 8

What is the treatment for HCV?

Answer 8

PEG-IFN + Ribavirin + Protease inhibitor

PEG-IFN: contra with depression, liver failure
Ribavirin: teratogenic, Hematotoxicity

Question 9

Why is HCV curable as opposed to HBV?

Answer 9

HCV is an RNA virus, thus never goes to the nucleus

Question 10

What are the microbiological characteristics of HDV?

Answer 10

Delta virus with circular ssRNA

Contains Delta-Ag + HBsAg

Question 11

What is unique about the disease caused HDV?

Answer 11

Always occurs as super infection in HBV patient

HDV requires HBV for transmission (not replication)

Question 12

What is the pathogenesis of HDV?

Answer 12

HBsAg facilitates hepatocyte infection
Delta-Ag is a polymerase molecule that copies genome.
Doesn’t produce it’s own receptor thus it uses HBsAg from HBV for infection.

Question 13

What is the clnical presentation of HDV infection?

Answer 13

HBV infection that suddenly gets a lot worse.

Question 14

What are the microbiological characteristics of HEV?

Answer 14

ssRNA+ non-enveloped iscosahedral capsid

Family: Calcivirus
Genus: Hepevirus

single serotype

Question 15

What disease is classically associated with HEV?

Answer 15

Acute enterally transmitted hepatitis

Question 16

What are the important epidemiological facts about HEV?

Answer 16

1. Most prevalent in developing world
2. Pregnant women = higher fatality risk
3. Swine may be important reservoir

Question 17

What is the pathogenesis of HEV?

Answer 17

Transmitted F/O route –> replicates in GI tract (15-30 days) –> Liver, Kidney, Spleen –> Sheds (jaundice)

Same as HAV

Question 18

How is HEV diagnosed?

Answer 18

Same as HAV: isolated from patients feces

Question 19

What are the microbiological characteristics of HGB?

Answer 19

Flaviviridae

ssRNA+

Question 20

What are the epidemiology and disease characteristics of HGV?

Answer 20

non A/B-PT hepatitis

common in blood donor populations