Viral Gastroenteritis Flashcards Preview

Unit 1 ID+LC > Viral Gastroenteritis > Flashcards

Flashcards in Viral Gastroenteritis Deck (18):
1

Does viral gastroenteritis present with watery or bloody diarrhea? Does vomiting usually precede or follow?

ACUTE onset watery diarrhea
(w/o mucous/blood like bacteria)

Vomiting often precedes if it is present

2

Viral gastroenteritis:
- short or long periods?
- duration of symptoms?
- why does it persist even after you poo?
- stable or unstable?
- seasonal or year round?

Short incubation period

Short duration of sx

Prolonged shedding in stool
- can infect others

Stable: lasts for days on surfaces
- highly transmissible

Seasonal: winter

3

How common are virus causes of gastroenteritis?
List common types of virus that cause it.

virus cause >75% of gastroenteritis

1. Caliciviruses
- norovirus
- sapovirus

2. Rotavirus

3. Enteric adenovirus

- lots of different serotypes

4

Vaccines for which virus is available against gastroenteritis?
Name them

rotavirus
1. RotaTeq (RV5)
- pentavalent live bovine

2. Rotarix (RV1)
- monovalent live hu

5

Norovirus
- DNA or RNA virus?
- enveloped?
- virulence factor?

small round ssRNA virus

- non-enveloped (naked)

- viral encoded protease cleaves viral protein --> replication

6

how many indiv infected with norovirus are asymptomatic?
Incubation + duration of sx?

1/3 asym (but can still shed virus in stool)

Fastest on and fastest off *
Incubation: 15 hours-2 days
Duration: 1-2 days

7

Most common cause of diarrheal outbreaks in older children and adults?

Norovirus
- also the 2nd most common cause of diarrhea in young children

8

Norovirus seasonality

year round
- with winter predom.

9

Norovirus immunology

short lived ~6 months
- frequent antigenic shift
- strain diversity

Host ab confers short-term protection

10

What gene can allow some indiv to be innnately resistant against norovirus?

FUT2

11

Rotavirus comes from which viral family?

Reoviridae

*gobstopper vrus

(note that noravirus comes from the calicivirus family)

12

Rotavirus
- DNA or RNA?
- enveloped?

dsRNA
nonenveloped
- but has 3 protein shells
1. outer capsid layer:
2. inner capsid layer
3. innermost

13

These layers of the rotavirus protein shells (not envelop) confer which virulence?
1. outer capsid layer:
2. inner capsid layer
3. innermost

1. outer capsid layer:
- acid stability
- VP7 with VP4spikes: neutralizing ab

2. inner capsid layer:
- VP6: major rotavirus group antigen

3. innermost
- VP2

14

Reassortment

allows introduction of segments from animal rotavirus into human rotavirus
-->
EPIDEMICS

15

Rotavirus enterotoxin

NSP4
- destabilizes membranes -->
cell death
- mobilizes intracellular Ca2+ -->
activ. signal transduction pathway to transport from ER

16

Incubation period and duration of Rotavirus

Incubation period: 1-3 days

Peak viral shedding on day 3

Symptoms: 4-8 days
- more severe than noravirus

*but still a self limiting disease

17

Single most important cause of severe infantile gastroenteritis world wide

rotavirus
- preventable w/ vaccine
- treatable by ORT

*peak at age 6-24 mo

18

Seasonality of rotavirus

predom: winter
- year round in tropics