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49 Cards in this Set

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Viral gastroenteritis:

- Primary symptom
- Associated symptoms x3
- Vital signs
WATERY DIARRHEA

Nausea/vomiting, mild fever

Usually NORMAL
What is a distinguishing feature between viral and bacterial gastroenteritis?
Viral has milder fever
Viral Gastroenteritis:

- severe/chronic disease associated with what conditions? x2

- death results from what events? x2
Immunodeficient
Malnutrition

Acidosis
Dehydration
Treatment therapy for viral gastroenteritis.

- prognosis
- children
- serious conditions
- what speeds recovery
Usually self limiting

Oral rehydration + electrolytes
(esp. for children)

IV rehydration + electrolytes
if serious

Feeding speeds up recovery
Besides the Rotovirus, Norovirus, and Astrovirus: name 5 other viruses associated with viral gastroenteritis.

Which one is seen primarly in:

- newborns
- children
Coronavirus (SARS) - newborns
Herpesvirus (CMV, HSV)
Adenovirus - children
Picornovirus
HIV
Adenovirus gastroenteritis is unique from other viral gastroenteritis viruses b/c of its longer.....
longer duration

longer incubation
Rotovirus genome:

- # of strands
- type of strand
- envelope?
- capsid shape
Double stranded

Plus and Minus

Non-enveloped

Icosahedral
Describe the dsRNA fragments associated with Rotovirus genome.
11 fragments

3 L
3 M
4 S
What is unique about the capsid structure of rotovirus?
2 Concentric capsids

(double layered)
For rotoviruses, why does 11 dsRNA fragments create 15 proteins?

Be specific
Most are monocistronic, except

M3 and S1 encode 2 genes

Thus 13 proteins (from 11 frag)
- 8 structural
- 5 nonstructural
What is the infectious form of the rotovirus called, and how do you get to that point?
ISVP - Intermediate SubViral Particle

Virus is proteolytically processed in the gut, allowing its conversion to ISVP.
In order for rotovirus to penetrate cytoplasmic membrane, the sigma1 attachment protein binds to what receptor?
Sialic acid
Rotovirus replication of the PARENTAL RNA will ALWAYS occur in:

a. Inner core
b. cytoplasm
c. nucleus
d. Outer core
e. 2 of the above
f. 3 of the above
g. none of the above
h. all of the above
E.

Occurs in cytoplasm and inner core
In rotoviruses, the negative strand is:

a. capped
b. polyadenylated
c. copied to dsDNA
d. template
e. 2 of the above
f. 3 of the above
g. none of the above
h. all of the above
F.

It is capped, polyadenylated, and used as a template

Only the positive strand gets converted into dsDNA
Describe what is meant by the triple layer formation for rotoviruses.
During replication, it will bud in to the ER, which will add the outer layer and the envelope, giving it three layers total.

However, during release, the envelope is lost
Rotovirus groups:

- name all
- which infect humans
- which infects kids
- which infects adults
- which allow for reassortment?
A-G (seven types)

A - kids
B - adults
C - unknown

A,B, and C can do reassortment
Rotovirus gastroenteritis:

- transmission
- survival ability
- incubation
- peak months
- affects of humidity
Fecal-oral

Can survive 7 months in shit

Less than 48 hours

Cooler months

High humidity INACTIVATES it
Low humidity makes it STRONGER
Target cell of Rotovirus.

Include location
Columnar Epithelial Cells

covering VILLI

of SMALL INTESTINE
Rotovirus disease would manifest what on histologically?
Shortening/blunting of villi

Mononuclear infiltrate of lamina propria

Epithelial Damage
In general, list the 2 mechanisms used by rotovirus to cause pathology.
1. Shuts OFF host cell function

2. NS protein acts as Enterotoxin
Describe the effects of enterotoxin for rotovirus gastroenteritis. x2
Promotes influx of calcium

Promotes defect of water absorption
For rotovirus gastroenteritis, what is found in the gut, that correlates with disease severity?
IgA
Is rotovirus gastroenteritis mainly symptomatic in children or adults?
Children

Adults are usually asymptomatic
ROTASHIELD vaccine:

- contains what?
- how well used in the US?
- side effect
Contains live, attenuated virus

Currently suspended in US

Due to INTUSSUSCEPTION (folding of intestines)
What are some other rotovirus vaccines being tested now and what is in them?
ROTAteq - bovine strain

ROTArix - human strain
Calciviruses:

- RNA or DNA
- # of strands
- plus or minus strand
- envelope
- capsid
RNA

Single stranded

Positive (plus)

NON-envelope

Icosahedral
T/F - Calcivirus has a 5'cap

T/F - Calcivirus is polyadenylated
False - has a VPg

True
Why is the calcivirus capsid so unique? x3
EXTREMELY stable

90 Dimers of capsid proteins

Does NOT require RNA interaction for proper folding
What is the #1 cause for food-borne gastroenteritis?

What is the #1 cause for viral food-borne gastroenteritis?
Norovirus (50% of total)

Norovirus (96% of viral)
How long does it take for the 1st symptom to occur after infection for Norovirus gastroenteritis?
24 hours
Transmission routes for norovirus gastroenteritis. x3
Fecal-oral

Fomites

Aerosolized vomitus
T/F - Norovirus is associated with PEDS gastroenteritis.
False, mainly adults
What is the best course of prophylactic action against norovirus gastroenteritis?
Wash hands and use gloves
What are the 5 characteristics of Norovirus that make is facilitate easy spreading?
1. Sustained Strain DIVERSITY

2. Prolonged Asymptomatic SHEDDING

3. Environmental STABILITY

4. Lacks LASTING IMMUNITY

5. Low INFECTIOUS DOSE
What is the infectious dose level for norovirus gastroenteritis?
Less than 100 particles
T/F - Childhood infection of Norovirus will protect adults for future infections.

Why or why not?
False.

Unknown reason as to why there is a lack of lasting immunity
What is the molecular mechanism associated with the Norovirus pathogenesis?
unknown
What is the infected cell type for the norovirus?
unknown
With all the diversity existing for Noroviruses, what interesting factor exists in humans that differentiates which noroviruses are susceptible and resistant?
Blood types
Describe the pathology seen in Norovirus gastroenteritis. x2

What makes this different from Rotoviruses?
Blunted/Shortened villi in proximal small intestine

Mononuclear cell infiltrate into the lamina propria

Epithelial cells are INTACT, unlike the effects seen in rotoviruses.
What clinical symptoms has a stronger association with Norovirus gastroenteritis than other virueses?
Vomiting

Seen in >50% of cases
Diagnosis tests for Norovirus gastroenteritis. x2
Antibody staining (stool)

RT-PCR (stool)
Norovirus gastroenteritis:

- Incubation
- Duration of illness
1 to 2 days

12 to 60 hours
Which viral gastroenteritis virus has the potential for bioterrorism?
Calciviruses (RHDV, FCV)
Astroviruses:

- RNA or DNA
- # of strands
- plus or minus strand
- envelope
- capsid
RNA

Single stranded

Plus

NON-enveloped

Icosohedral
Astrovirus gastroenteritis is a problem for adults or children?
Main children

Adults are usually asymptomatic
Astrovirus gastroenteritis:

- transmission
- incubation
- duration
- # of serotypes
fecal to oral

3-4 days

3-4 days

8 types
Compare the symptoms of gastroenteritis caused from astrovirus vs. rotovirus.
Both affect children, but

astrovirus is more MILD in diarrhea
Astrovirus:

- lasting immunity?
- who are most at risk
Yes, but does wane with age

Immunocompromised
(12% of HIV patients)