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