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75 Cards in this Set

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Virus family of Hep A
Picornaviridae
Virus family for Hep B
Hepadnaviridae
Virus family for Hep C
Flaviviridae
Virus family for Hep E
Caliciviridae
Type of virus Hep D is
Defective ssRNA virus
What causes cellular damage in hepatitis?
The Immune Response

Actual virus growth is relatively benign for hepatocytes
% of Hep B carriers that develop chronic, active hepatitis
25%
Predominant Hep B serotype in the U.S.
adw
HBV can be disinfected by
Bleach
Acid
Unlike most enveloped viruses, HBV CANNOT be inactivated by these
Detergent
Ether
Dane particle
Name for the infectious virion of HBV
Size of the two particles that accompany Dane particle
20 nm

One is a rod, one is a sphere
What are the two particles that accompany the Dane particle made of?
Composed entirely of S glycoprotein (HBsAg)
Unique characteristic of Hepatitis virus
PARTIALLY double stranded

Full length minus strand
50-80% complete positive strand
What are the four proteins encoded by HBV?
HBsAg
HBcAg
Polymerase
Protein X (function unknown)
What is special about HBV polymerase?
Has BOTH RNA-dependent and DNA-dependent (reverse) polymerase activities
Three forms of HBsAg
Small
Medium
Large

ALL are present in virions
Predominant form of HBsAg in Dane, spherical and rod-shaped particles
Small form
HBeAg
Truncated form of HBcAg that is secreted by infected cells
Function is unknown
In what cells does HBV replication take place?
Hepatocytes
Where in the cell does HBV replication take place?
Nucleus
cccDNA
Covalently Closed Circular DNA

This is what HBV DNA becomes after missing nucleotides of + strand are added
Where is the + strand of the DNA made complete?
In the nucleus
What is packed in the initial capsid with the full-length transcript?
Core protein
HBV Polymerase

NOTE: remember that the transcript is RNA
Inside the capsid, what is done with the transcript?
Complete MINUS DNA strand is synthesized from it

Minus strand DNS is template for incomplete PLUS strand DNA
What does HBV bud through?
Cytoplasmic VESICLE
How does HBV exit the host cell?
Exocytosis
How is HBV transmitted?
Parenterally (needles, sex, birth, etc.)

HBV present in all body fluids, including mother's milk
Is rate of progression to chronic infection higher in children or adults?
Children (80-95%)

In adults, it is only 5-10%
Incubation period for HBV
Two months or more
Are there more virions or 20 nm particles in blood?
20 nm particles
"Window period" of HBV infection
When neither HBsAg nor anti-HBs can be detected

After HBsAg has largely disappeared
Before anti-HBs has shown up

NOTE: Abs for HBc and HBe are detectable in this period
Serology of HBV chronic carriers key characteristics
HBsAg does NOT go away
Anti-HBs never shows up
In what order do the following show up?

Anti-HBs, Anti-HBc, Anti-HBe
Anti-HBc --> Anti-HBe --> Anti-HBs

NOTE: in chronic carrier state, Anti-HBs never shows up
When (what period) does Ab for HBsAg show up?
During the recovery period

SO, it doesn't contribute significantly to clearing
In an HBV infection, what do CD8 T cells recognize?
Fragments of HBcAg
Where (in the world) is HBV carrier rate high?
Southeast Asia
Africa
Type of vaccine for HBV
Subunit vaccine consisting of HBsAg

Given in three doses
Most widely used drug against HBV
Lamivudine
Timeline of HBV dosage
1st dose is time 0
2nd dose 1 month after first
3rd dose 6 months after first
What is given to babies right after birth to prevent HBV?
HB immune globulin
HDV is also known as what?
Delta agent
HDV requires what other virus in order to propagate?
HBV
When is disease more severe?

HDV and HBV simultaneous co-infection

OR

HDV super-infection in an HBV carrier
HDV super-infection in an HBV carrier

Rate of fulminant hepatitis is greater
Progression to carrier state occurs to greater extent
Characteristics of HDV genome
MINUS sense
ssRNA

Enclosed in capsid of Delta antigen
Wrapped in membrane containing HBsAg
What one protein does HDV genome encode?
Delta antigen
How is HDV transmitted?
Same as HBV
EXCEPT, NOT by sexual route
What is the only real method to control HDV?
Vaccination for HBV
What is the etiological agent for "acute" (infectious) hepatitis?
Hepatitis A
How many serotypes of HAV are there?
Only ONE
How is HAV transmitted?
Fecal-oral route
HAV is inactivated by... (5)
Bleach
Formalin
Beta-propriolactone
UV radiation

Routine chlorination of drinking water
Large quantities of HAV can be found where (in/from body)?
In bile
In stool
Onset of symptoms in HBV is described as
Insidious
Onset of symptoms in HAV is described as
Acute
Incubation period for HAV
Approximately 4 weeks
After recovery from infection, what is HAV immune status of pt.?
Life-long immunity

There are NO CHRONIC CARRIERS
What is the course of HAV hepatitis?
Symptoms last for 3-4 weeks
Infection resolves completely
How is HAV diagnosed?
Analyzing stool w/ PCR or immunoassay
ELISA assay for anti-HAV in blood
Is HAV more symptomatic in adults or children?
Adults (3:1, symptomatic:asymptomatic)

Children (1:12)
Type of vaccine for HAV
Killed
In the U.S. are there more carriers for HBV or HCV?
3x as many HCV carriers
HCV-encoded proteins do what to the immune response?
Antagonize it
Inhibit apoptosis
Antagonize effect of interferon
How is HCV transmitted?
Parenterally (Sex, blood, needles)
Incubation period for HCV
1 - 2 months
When can viremia be detected in an HCV-infected pt.?
After 1 - 3 WEEKS

Lasts 4-6 months in those who clear infection
Last for life in chronically infected
How long does it take for most pts. to become anti-HCV positive?
Usually happens within 5 MONTHS (7 - 31 weeks)
% of people who become HCV chronic carriers
85%
This enhances the progression of HCV chronic carriers to liver disease
Alcohol abuse
% of deaths from chronic liver disease attributed to HCV
40%
This has been successful in clearing carrier state of HCV in some pts.
Combo of interferon and ribavirin
Pt. group at risk for severe HEV infection
Pregnant women

20% mortality in this group
Hepatitis viruses with parenteral transmission
HBV
HCV
HDV
Hepatitis viruses with fecal-oral transmission
HAV
HEV
Hepatitis C genotype that is most common in U.S.
Genotype I

Shows poor response to treatment