GI Infections 2

Question 1

vaccines for HBV are made against _____

Answer 1

surface envelope glycoprotein

Question 2

acute infection of HBV is characterized by the presence of which antigens?

Answer 2

HBsAg and HBeAg (surface and early antigen)

AND IgM against the core antigen

Question 3

what would you expect to see in a chronic infection of HBV

Answer 3

• anti HBc (antibodies against HBc)

- HBs Ag and HBeAg detected for years

Question 4

HDV Is ______ sensed ____ genome

Answer 4

negative sense ssRNA genome

Question 5

what is the window period?

Answer 5

the time frame between the absence of the surface antigen and the antibody to it so during this period is measured using the IgM against the core antigen (anti-HBc)

Question 6

serology results:

• HBsAg +
• anti- HBc +
• IgM anti HBc -
• anti HBs -

Answer 6

someone who has been chronically infected by HBV

Question 7

to kill HBV infected hepatocytes, MHC Class I restricted and CD8 T cells are directed against __________

Answer 7

HBcAg (core) and HBsAg (envelope)

Question 8

antibody against ____ is a marker for acute infection of HBV, especially during the window period

Answer 8

IgM against core antigen (HBcAg)

Question 9

mammals ingest ______ form of fasciola

Answer 9

metacercariae

Question 10

describe the life cycle of Fasciola

Answer 10

• eggs release miracidia which invade snails
• cercariae released from snails and encyst as metacercariae on aquatic vegetation
• mammals ingest the metacercariae and they excyst in the duodenum
• migrate to the intestinal wall/peritoneal cavity and liver parenchyma into the biliary ducts

Question 11

___ is the form of fasciola that invades snails

Answer 11

miracidia

Question 12

which is more infective? HBV or HIV?

Answer 12

HBV; HBV remains infective in blood outside the body for up to 7 days

Question 13

Hepatitis B virus is a RNA/DNA virus belonging to the family ________

Answer 13

DNA virus from the Hepadnaviridae family

Question 14

once HBV gets to the liver, it targets the _____

Answer 14

hepatocytes and Kupffer cells but it is NOT directly cytopathic to liver cells

Question 15

if HBsAg is positive, that indicates _____

Answer 15

current infection: acute or chronic

Question 16

metacercariae excyst in the ______ of the human

Answer 16

duodenum

Question 17

name 3 trematodes associated with the biliary tree

Answer 17

• fascioliasis
• clonorchiasis
• opistorchiasis

Question 18

what are the surface glycoproteins found on HBV?

Answer 18

surface antigens: S, M, and L (small medium and large)

Question 19

you see Anti-HBc in serology. what is this indicative of?

Answer 19

window period (acute infection)

Question 20

describe the genome of HDV

Answer 20

• enveloped negative sense RNA genome single stranded rod shaped

Question 21

when HBV is creating the partial dsDNA using the RT, the RNA part has to be degraded by RNAase H. what protein in the HBV ORF has this activity

Answer 21

ORF P

DNA polymerase, RT and RNase H activity

Question 22

describe the replication process of HBV:

Answer 22

1. once in the host nucleus, HBV will fix its partial dsDNA and create a covalently closed circular DNA (CCC)
2. host DNA dependent RNA polymerase generates 4 mRNA’s of which 1 is full length RNA
3. HBV’s reverse transcriptase then converts the pre genomic full length RNA to partial dsDNA

Question 23

if a patients serology for anti-HBs is positive, what are some possibilities for their infection status of HBV

Answer 23

• immune dune to natural infection

- immune due to HBV vaccination

Question 24

which hepatitis is part of the hepadnaviridae family?

Answer 24

HBV

Question 25

is HBV enveloped? describe the structure of its genetic material

Answer 25

enveloped but relatively resistant to freezing, detergents and moderate heat.
partial dsDNA circular genome (one strand is larger than the other)

Question 26

______ codes for the HBeAg (early antigen) in HBV

Answer 26

ORF C; also code for the HBcAg

Question 27

acute/chronic form of HBV can develop into hepatocellular carcinoma

Answer 27

chronic

Question 28

HBV is stable/unstable at low pH

Answer 28

stable (unique)

Question 29

replication of HBV occurs in _______

Answer 29

host nucleus

Question 30

why does HDV require the presence of HBV to survive?

Answer 30

• HDV envelope contains HBsAg derived from HBV

Question 31

intermediate host of the fasciola is _______

definitive host is:

Answer 31

intermediate host: snail

definitive host: sheep, goat, cattle and other herbivores from which shed the fasciola sp. in their feces

Question 32

What is a Dane particle?

Answer 32

non infectious HBV viral particles that are there to produce an immune response (cytokine storm) but have no genetic material inside to replicate (act as a decoy)

Question 33

infective form of fasciola is _______

Answer 33

metacercariae (same with C. bu the intermediate host is fish)

Question 34

______ protein is responsible for the poly or monoclonal expansion of the cell in HBV infection. It is coded for by _________

Answer 34

HBx protein coded by ORF X

Question 35

when you see positive anti-HBs what are some possibilities for the infection status of HBV in that patient

Answer 35

• immune dure to naturel infection or immune due to HBV vaccination

Question 36

what is the form of fasciola that you can find on the aquatic vegetation

Answer 36

metacercariae

Question 37

ORF S codes for _______ in HBV

Answer 37

surface proteins (S, M, or L)