hepatitis

Question 1

Hepatitis

Answer 1

a clinical syndrome characterized by

inflammation of the liver

Question 2

why is jaundice associated with hepatitis

Answer 2

hepatocyte cell death releases bilirubin, which causes jaundice
bilirubin is a biproduct of heme metabolism in the liver (where heme is detoxified)

Question 3

hepatitis viruses trophism

Answer 3

strong tropism for the liver and preferentially replicate in the hepatocyte
85% of liver cells are hepatocytes
Therefore these viruses primarily cause liverdisease

Question 4

2 main modes of action for hepatitis viruses
strains?
transmission

Answer 4

Question 5

HepA genome and family

Answer 5

linear +ssRNA

picornaviridae

Question 6

HepA causes what kind of hepatits

Answer 6

infectious hepatitis

Question 7

HepA strucutre

Answer 7

icoshedral naked capsid

Question 8

HepA transmission

Answer 8

spread by fecal-oral contamination of food, drink, or shellfish

Question 9

HAV shedding/ effect on hepatocytes

Answer 9

HAV shed into bile ducts and into intestine and passes out of the body in the feces
HAV directly kills hepatocytes

Question 10

clinical manifestation of HAV infection (HepA)

Answer 10

–usually mild intestinal infection

–occasionally viremia occurs, leading to liver infection= jaundice

Question 11

prevention and treatment HAV

Answer 11

killed HAV vaccine (now recommended for all in US, esp. for military, frequent travelers, staff of care facilities)
Post-exposure immune globulin

Question 12

HAV highly endemic regions: children and adult from non endemic regions

Answer 12

In highly endemic regions, almost all children become infected in first few years of life
- most remain asymptomatic
- adults from nonendemic regions who become infected are more likely to display
symptoms

Question 13

HepB genome and family

Answer 13

nicked circular, mostly dsDNA

hepadnaviridae

Question 14

Hep B envelope

Answer 14

enveloped

Question 15

genome size HepB

Answer 15

smallest at 3200 bp

Question 16

viral particles of hepB

Answer 16

–22 nm particle
–Variable tubular/filamentous particle (22 nm diameter)
–42 nm Dane particle (infective form of virus)

Question 17

surface Ag of HepB

Answer 17

L,M, and S, embedded in the lipid bilayer envelope

HBsAg-S is the main component

Question 18

core Ag of hepB, useful?

Answer 18

HBeAg is a processed form of the core, HBcAg.

HBeAg is mostly secreted from infected cells and found in bloodstream. Useful marker for HBV infection.

Question 19

filament form of hepB enriched for?

Answer 19

HBsAg-L

Question 20

HepB replication cycle

Answer 20

receptor mediated endo
core particle enters host nuc
undergoes repair to form full dsDNA circle
use of host RNA transcriptase
RNA out of nuc may be translated
RT occurs during viral assembly, unlike retroviruses (DNA made), Reverse transcription is by
viral reverse transcriptase
Budding from ER and vesicular transport to cell mem for release

Question 21

HepB RT priming

Answer 21

Priming of reverse transcription by TP (terminal protein domain) of viral polymerase by adding first nucleotide to a tyrosine residue of TP

Question 22

what determine course of HepB infection

Answer 22

Cell-mediated immune response- Cytotoxic T lymphocytes kill infected hepatocytes

Question 23

effective CMI with HepB

Answer 23

Question 24

non-effective CMI with HepB

Answer 24

Question 25

how does HBV kill hepatocytes

Answer 25

HBV does not directly kill hepatocytes Cytotoxic T lymphocytes directed against MHC class I proteins bound to viral antigens on hepatocyte surface Killing also occurs by cytokine release that promotes inflammation and tissue damage

Question 26

Outcomes of acute HBV infection

Answer 26

Question 27

infants and HBv infection outcome

Answer 27

90% become chronically infected due to not fully developed Immune response

Question 28

Hepatocellular carcinoma - why?

Answer 28

increased cell division due to regeneration - increases chances of mutations peroxides and free radicals from CTL killing

Question 29

``` Serology of HBV infections HbsAg, ANTI Hb s, ANTI Hb c, ANTI Hb e, HbeAg no exposure prior vax resolved acute infection acute/chronic infection late stage chronic ```

Answer 29

Question 30

prevention HepB | HBsAg particles produced in?

Answer 30

vaccination recommended for all infants in USA | –HBsAg particles produced in yeast

Question 31

treatment HepB

Answer 31

–passive immunotherapy within 7 days of exposure | anti RT drugs

Question 32

HepD genome and family

Answer 32

circular -ssRNA | deltaviridae

Question 33

HDV depends on what other Hep and why

Answer 33

Depends on HBV virus to replicate (provides | envelope protein)

Question 34

chronic HBV and HDV

Answer 34

Chronic HBV infection exacerbated by infection with hepatitis delta virus

Question 35

HepC genome and family

Answer 35

linear +ssRNA | flaviviridae

Question 36

HepC envelope?

Answer 36

enveloped

Question 37

HCV spread routes

Answer 37

In addition to HCV transmission through blood and sexual fluid, HCV also spreads from mother to fetus, by fecal-oral route, and through organ transplants

Question 38

how does HCV kill hepatocytes

Answer 38

HCV also does not directly kill hepatocytes Cytotoxic T lymphocytes directed against MHC class I proteins bound to viral antigens on hepatocyte surface Killing also occurs by cytokine release that promotes inflammation and tissue damage

Question 39

HCV replication cycle

Answer 39

``` receptor binding and endo uncoating +RNA translated/ polyprotein made = RNA poly made RNA replication (+ to - then to more +) virion assembly and release ```

Question 40

HCV RNA poly error

Answer 40

``` Viral RNA polymerase is error-prone, creating multiple viral variants (= quasi-species) (like HIV) ```

Question 41

HCV infection outcomes

Answer 41

Question 42

HepE genome and family

Answer 42

linear + ssRNA | caliciviridae

Question 43

HepE replication cycle

Answer 43

receptor endo uncoating and translation of RNA = polypro = viral RNA poly replication of RNA = full genome and subgenomic for more proteins assembly and release without budding (naked capsid virus)

Question 44

HepE transmission

Answer 44

spread in contaminated food and drink (like HAV) | • human-to human transmission and animal-to-human transmission (common source = pigs) (zoonosis).

Question 45

HEV shedding/ effect on hepatocytes

Answer 45

HEV shed into bile ducts and into intestine and passes out of the body in the feces HEV directly kills hepatocytes