L81

Question 1

What are the major viral causes of diarrhea?

Answer 1

1. Rotavirus
2. Caliciviruses
   - Noro
   - Sapo
   Enteric adenovirus, astrovirus

Question 2

Rotavirus genome

Answer 2

DOUBLE stranded RNA
Segmented
Naked
“Wheel with spokes”

Question 3

What are VP4 & VP7? Similarities vs differences?

Answer 3

Rotovirus OUTER capsid antigens 
Both involved in neutralization 
VP7 : G protein
vs 
VP4 : P protein 
G + P determine serotype

Question 4

How do you diagnose rotavirus?

Answer 4

VP6 = inner capsid antigen

Stool sample –> immuno-assay for this

Question 5

What is the most common rotavirus serotype?

Answer 5

G1P8

Question 6

How and where is rotavirus activated?

Answer 6

@ gut

Proteases remove VP7

Question 7

Which surface antigen mediates attachment for rotavirus?

Answer 7

VP4

Attachment to gut

Question 8

How is rotavirus released from host cells?

Answer 8

Lysis - naked virus

Question 9

What type of diarrhea does rotavirus cause? Name the 3 possible mechanisms.

Answer 9

Watery diarrhea
1. Cytolytic infection of intestine villi –> blunting of microvilli –> less water absorbed
Actin rearrangement
In response, secretory crypt cell migrate out to repair damage faster, but they are immature –> increased water secretion
2. Entertoxin mediated by NSP4 (non-structural) protein
3. ENS activated - increased secretions

Question 10

Rotavirus transmission

Answer 10

Fecal-oral… makes sense

Question 11

Is rotavirus more common in adults or kids?

Answer 11

Kids

Question 12

Incubation and disease timelines for rotavirus

Answer 12

Incubate = 2 days
Sick = 4-8 days

Question 13

Rotavirus complications

Answer 13

1. Dehydration
   Electrolyte changes/malabsorption
   Diarrhea
   Acidosis

Question 14

Where in the world is rotavirus common?

Answer 14

Bangladesh or West Africa

Question 15

Describe current rotavirus vaccines

Answer 15

Live, oral, attenuated

Very effective - given example of herd immunity

Question 16

Enteric adenovirus genetics - include relevant serotypes

Answer 16

dsDNA
Icosahedral capsid w/ penton fibre at each apex
2 serotypes - 40 & 41

Question 17

If enteric adenovirus has the same symptoms as rotavirus, how do you tell them apart?

Answer 17

Enteric = longer timeframe
- 5-12 days sick
P2P transmission

Question 18

Astrovirus genetics

Answer 18

+ssRNA

Naked

Question 19

Astrovirus transmission and duration of illness

Answer 19

P2P transmission (or food/water)
3-7 days sick

Question 20

Caliciviruses genetics

Answer 20

+ ssRNA

Naked

Question 21

2 major caliciviruses

Answer 21

Noro
Sapo
Infection with these is SUPER common

Question 22

What is the seasonality of calico viruses?

Answer 22

Noro peaks in winter

But environmentaly stable

Question 23

Calici virus transmission

Answer 23

**LOW infectious dose
P2P
Fecal-oral
Air - kids daycare

Question 24

Which blood type has increased risk for calico infection

Answer 24

Grp O

Question 25

Describe how you would test the enteric viruses for infection

Answer 25

1. Rota - immuneassay for grp A antigen
2. Enteric - serotyping for 40/21
3. Calici and astrocytes - nothing available