Diebel: Viral Gastroenteritis Flashcards
What is the most common route of transmission for viral gastroenteritis?
fecal oral
How does viral gastroenteritis cause secretory diarrhea?
infection and damage to the proximal bowel
If you have viral gastroenteritis, does your stool contain leukocytes?
NO (usually bacterial)
What are common sxs of gastroenteritis?
nausea
vomiting
abdominal pain
What viruses tend to cause more severe vomiting?
noroviruses (less common for rotavirus)
Do you treat viral gastroenteritis?
No, it’s self limiting, but w/out supportive care can lead to death in hard to reach areas of the world.
What are the major causes of viral gastroenteritis?
rotavirus (winter, young children <5)
norovirus- norwalk virus (outbreaks of food borne illness, adults, year round)
What are the minor causes of viral gastroenteritis?
adenovirus
astrovirus
Rotavirus
RNA virus icosahedral nonenveloped (but it's double shelled!) class III- DS, segmented Reoviridae
REO- respiratory enteric orphan
*related to coltivirus
What is unique about the capsid of the rotavirus?
The segmented genome of the rotavirus is significant b/c…
Double shelled *very stable
You can get reassortment of the genes to create new strains.
What are the natural hosts for rotavirus?
humans
vertebrates
*host-range restricted
What is the tropism for rotavirus?
Mature absorptive villous epithelium of the upper 1/2 of the SI.
What happens to Rotavirus after replication in the SI? What is the virus confined to?
infectious particles are released into the intestinal lumen> undergo further replication in the distal areas of the small intestine.
Infection is generally confined to the intestinal mucosa
How does Rotavirus replicate w/in the cell?
RNA particle brings everything it needs for trxn. As the virus particle is released from the infected cell it dies through lysis and death causes diarrhea symptoms. When the virus is immediately released, the second core needs to go through maturation in the SI, and then it will be infectious.
What is the only example of a viral toxin protein?
NSP4 (enterotoxin)
Viral protein that has a cytotoxic affect in the SI. NSP4 can lodge in the lumen and disrupt Ca stores in the cells which contributes to cell death and the secretion of ions into the small intestine further exacerbating diarrhea.
How does rotavirus attack and wreak havoc in your body?
- Affects epithelial cells of SI
- 8 hrs post infection> begin to see cytoplasmic inclusions where replication is taking place
- At height of infection you can get 10 billion viral particles/ g of stool
What is the global distribution of deaths from rotavirus?
More common in parts of the world where malnourishment is more common.
Almost every child under 5 will have a rotavirus infection, but if you have vit A def it can exacerbate the infection.
What vaccines are used to treat rotavirus?
Rotarix
Rotateq
Rotarix
Live attenuated
Made of human strain of virus that’s been attenuated
Rotateq
Live attenuated
hybrid between human and cow strain of rotovirus. Hybridization of virus particle allows it to be attenuated
Norwalkvirus-Norovirus
RNA icosahedral non-enveloped IV SS+ non-segmeneted calciviridae calcivirus
*adults, all year around, cruise ships, accounts for 50% of all foodborne gastroenteritis
What sxs are associated w/ norovirus?
What is a distinguishing feature of fevers in norovirus?
diarrhea vomiting abdominal cramps nausea HA anorexia Fever
no higher than 101 F
*High mutation rate and high number of strains means that immunity is short lived.
What is GII.4 Syndney?
New strain of norovirus
Strain emerged in March 2012 in Australia. Has quickly become the predominate strain causing both cruise ship and land-based outbreaks worldwide.
Norovirus can mutate quickly (causing DRIFT). Results in new strains every few years.
Norovirus infections are the leading cause of gastroenteritis in the US causing about 21 million infections each year and 800 deaths
Adenovirus (40-42)
DNA icosahedral nonenveloped I- DS DNA linear Adenoviridae Mastadenovirus
*Tissue tropism for Sml Intestine (40-42)
