L81 Flashcards Preview

Viruses & Parasites > L81 > Flashcards

Flashcards in L81 Deck (25):
1

What are the major viral causes of diarrhea?

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

2

Rotavirus genome

DOUBLE stranded RNA
Segmented
Naked
"Wheel with spokes"

3

What are VP4 & VP7? Similarities vs differences?

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

4

How do you diagnose rotavirus?

VP6 = inner capsid antigen
Stool sample --> immuno-assay for this

5

What is the most common rotavirus serotype?

G1P8

6

How and where is rotavirus activated?

@ gut
Proteases remove VP7

7

Which surface antigen mediates attachment for rotavirus?

VP4
Attachment to gut

8

How is rotavirus released from host cells?

Lysis - naked virus

9

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

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

10

Rotavirus transmission

Fecal-oral... makes sense

11

Is rotavirus more common in adults or kids?

Kids

12

Incubation and disease timelines for rotavirus

Incubate = 2 days
Sick = 4-8 days

13

Rotavirus complications

1. Dehydration
Electrolyte changes/malabsorption
Diarrhea
Acidosis

14

Where in the world is rotavirus common?

Bangladesh or West Africa

15

Describe current rotavirus vaccines

Live, oral, attenuated
Very effective - given example of herd immunity

16

Enteric adenovirus genetics - include relevant serotypes

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

17

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

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

18

Astrovirus genetics

+ssRNA
Naked

19

Astrovirus transmission and duration of illness

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

20

Caliciviruses genetics

+ ssRNA
Naked

21

2 major caliciviruses

Noro
Sapo
Infection with these is SUPER common

22

What is the seasonality of calico viruses?

Noro peaks in winter
But environmentaly stable

23

Calici virus transmission

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

24

Which blood type has increased risk for calico infection

Grp O

25

Describe how you would test the enteric viruses for infection

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