17 - HAV

Question 1

T or F: HAV can still happen in North America

Answer 1

T

Question 2

_______________ are a common source of HAV

Answer 2

Frozen berries

Question 3

T or F: It takes a long time for HAV to become symptomatic

Answer 3

T, symptoms appear between 15 and 50 days after infection

Question 4

Symptoms of HAV include:

Answer 4

• yellow eyes
• yellow skin
• abdominal pain
• pale stools

Question 5

HAV has effects on the human _______

Answer 5

liver

Question 6

When symptoms occur, they typically last _______

Answer 6

8 weeks

Question 7

T or F: acute liver failure may occur, but this is generally limited to elderly patients

Answer 7

T

Question 8

Can HAV spread via the fecal-oral route?

Answer 8

YES

Question 9

_____________________ seafood is a common vector of transmission

Answer 9

undercooked contaminated

Question 10

The _____________ is effective against transmission and is indeed recommended for anyone travelling to areas with lower sanitation standards

Answer 10

HAV vaccine

Question 11

T or F: after a single infection a person is immune for the rest of their life, and the vaccine appears to be effective for life

Answer 11

T

Question 12

T or F: no specific treatment is available for HAV

Answer 12

T

Question 13

________ is recommended and _________ may be used to treat the nausea and diarrhea on as-needed basis

Answer 13

Rest

medications

Question 14

Treatment of acute liver failure, if it occurs, is with a liver _______

Answer 14

transplant

Question 15

About _____ of children in the developing world will have a HAV infection before the age of 10, most of these infections are __________ and these children will then have immunity as adults

Answer 15

90%

asymptomatic

Question 16

Give the characteristic of HAV:

Answer 16

ssRNA (+)
non-enveloped
7500 bp long just like polio

Question 17

HAV has one serotype and 7 different genetic groups (____ human and __ non-human primate)

Answer 17

4

3

Question 18

The human genotypes are numbered _____

Answer 18

I-III

Question 19

6 subtypes have been described:

Answer 19

IA
IB
IIA
IIB
IIIA
IIIB

Question 20

The non-human primate genotypes have been numbered _______

Answer 20

IV-VI

Question 21

The HAV encodes a single ______ in which the major capsid proteins are coded for at the ________

Answer 21

polyprotein

N-terminal

Question 22

The remainder of the polyprotein encodes a series of _____________ required for HAV RNA replication

Answer 22

non-structural proteins

Question 23

A small protein, also known as ______, is covalently linked to the _____ end of the genomic RNA and this probably serves as the protein primer for RNA synthesis

Answer 23

VPG

5’

Question 24

Most of this virus appears to be produced in the _____ and reaches intestinal contents by _________ from infected hepatocytes via the ________ system

Answer 24

liver
secretion
biliary

Question 25

HAV life cycle:

Answer 25

- HAV binds to cellular receptor and gets into hepatocytes - It secretes its +sense ss RNA - The + ssRNA can be directly translated into the polyprotein - The polyprotein is cleaved to make subunits for the capsid and the things you need for RNA replication - +RNA can be reverse transcribed into -RNA which can then be used to make a lot more + RNA - +RNA can then be loaded into the assembled capsid - The assembled virus is secreted out via the biliary canalicus back into the intestinal tract

Question 26

Two types of antibodies are produced to get rid of the viral infection:

Answer 26

- IgM (immune response to a gastrointestinal infection - peaks around week 6 and gets rid of your infection over time) - IgG (peaks at 14 weeks out from the initial infection, IgG remains elevated as the IgM goes down - always stays up and is responsible for lasting immunity towards HAV)

Question 27

______ peaks a couple weeks after the fecal HAV peak

Answer 27

ALT

Question 28

ALT is a biomarker of ________

Answer 28

liver damage

Question 29

Fecal shedding of the virus reaches its maximum just before the onset of ______________ injury, at which point the individual is most infectious

Answer 29

hepatocellular injury

Question 30

______ is short lived but its presence is used to diagnose the illness

Answer 30

IgM

Question 31

How do you detect HAV in foods

Answer 31

- Food is collected and suspended in a glycine buffer and mixed for 15 minutes at room temp (the virus will become suspended in the buffer) - The supernatant from this mixture (containing the virus) is centrifuged at 170000 x g for 1 hour, at this speed the virus collects in a pellet at the bottom of the centrifuge tube - Supernatant is discarded - The pellet is resuspended in buffer and added to a QIA shredder to break the viral capsid and release the RNA - RNA is precipitated and purified and can then be used in an RT-qPCR reaction to detect its presence