GI Infections 6 Flashcards

1
Q

VP4 is the _____ antigen and its function is _________

A

“P” (Protease sensitive) antigen for the attachment to cellular receptors

has a projection out of the rotavirus capsid

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2
Q

what is the diagnostic and infective stage of cryptosporidium?

A

oocyst

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3
Q

describe the differences in the timing of the virus being shed in feces between norovirus and rotavirus

A

norovirus: 1 month after ingestion
rotavirus: peaks after 8 days

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4
Q

serotypes of rotavirus are based on group _____ and are classified based on ________. what are the most common serotypes?

A

Group A;
VP7 protein;
G1-G4 are the predominant strains in the US (G1 being most common)

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5
Q

what viruses commonly cause non inflammatory diarrhea in kids less than 5 years old

A

adenovirus, rotavirus and astrovirus

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6
Q

for diagnosis of cryptosporidium cause of diarrhea, you would see _______ on microscopic stool examination using a ________ stain

A

thick walled oocysts using a Ziehl Neelsen stain for the oocysts

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7
Q

cryptosporidium is a common cause of acute/chronic diarrhea in AIDS patients

A

chronic

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8
Q

what is a common risk factor for infection by cryptosporidium?

A

contaminated drinking or recreational water (swimming pools), due to municipal supply contamination through sewage/agricultural waste
the oocysts are able to resist chlorination

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9
Q

kids from 6-32 weeks are given what type of vaccine for rotavirus

A

live attenuated (usually won’t give live attenuated vaccine to kids less than 1 year old)

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10
Q

_______ is considered to be the most common cause of diarrhea in humans and death in children less than 5 years old

A

rotavirus

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11
Q

which protein in rotavirus is important for the attachment to cellular receptors

A

VP4 protein (P antigen)

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12
Q

G serotypes of rotavirus are based on _____ protein

A

VP7 protein

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13
Q

what is the age group of patients typically infected with rotavirus?

A

older than 6 months but younger than 5 years old

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14
Q

group ______ rotavirus is the most common cause of infantile gastroenteritis in the US

A

group A rotavirus

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15
Q

what is a dsRNA virus that causes non inflammatory diarrhea

A

Rotavirus (naked)

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16
Q

______ is the cause of 90% of all outbreaks of viral gastroenteritis

A

norovirus

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17
Q

the pathogenesis of rotavirus is similar to that of what bacterial cause of non inflammatory diarrhea?

A

EPEC because both disturb the structure of microvilli (blunting of the villi)

18
Q

VP7 is the _____ antigen

A

“G” (glycoprotein) antigen for different G serogroups of rotavirus

19
Q

which virus is associated with ingestion of raw shellfish? what is its biology?

A

norovirus (winter vomiting disease)

naked ss + RNA

20
Q

_________ is a virus part of the calciviridae family

21
Q

_____ (thin/thick) walled oocyst is responsible for intestinal auto infection

22
Q

describe the seasonality of norovirus infection

A

peaks in the winter

“winter vomiting disease”

23
Q

rotavirus replicates primarily in the _________. discuss the changes that occur with infection

A

villous epithelium of the SI → columnar epithelium at the villous tips are replaced by irregular cuboidal crypt-like cells leading to defect in fluid and electrolyte regulation

24
Q

what is the stage of cryptosporidium that is shed in the feces?

A

thick walled oocyst

25
the core of the rotavirus cottons: gene segments, viral _____ dependent _____ polymerase and capping enzymes
viral RNA dependent RNA polymerase
26
why is a live attenuated vaccine for rotavirus given to infants that are only 2 months old?
because the incidence if very high and starts very early (6 months) so the implementation of the vaccine must be earlier than this
27
in food poisoning due to ingestion of preformed toxins, the patient typically will develop symptoms within ______ hours after ingestion of the contaminated food
within 6 hours
28
which pathogens that cases non inflammatory diarrhea requires 100 viral particles to cause infections but sheds 10^6 particles in the feces making transmissibility very easy
rotavirus (11 segments dsRNA)
29
describe the biology of astroviruses
family: astroviridae - small NON ENVELOPED - + ssRNA (like norovirus)
30
is vomiting associated with norovirus infection?
yes (50% of patients have vomiting) but won't see vomiting in rotavirus infection
31
the ingestion of preformed toxins in B. cereus is found in ______ (food type) and causes _________
rice; emesis (emetic preformed ST neurotoxin)
32
describe the seasonality of rotavirus infections
- high income countries: during winter/spring | - low income countries: year long
33
in infection by cryptosporidium, the _____ (life cycle form) is infectious when shed
oocyst
34
Rotavirus is acquired via ____ or _____
fecal-oral or water borne with incubation period of 1-3 days
35
groups of rotaviruses is classified based on the antigenic epitopes on ________
protein VP6
36
P serotypes of rotavirus are used on ______ protein
VP4 protein
37
describe the biology of norovirus
- family: calciviridae - small NON ENVELOPED - + ssRNA
38
an AE of the live attenuated vaccine for rotavirus is ______
intussusception
39
cruise ship outbreaks with diarrheal and vomiting disease; the most likely causal pathogen is ______
norovirus
40
describe the structure and biology of rotavirus:
- family: reoviridae - wheel shaped - NON EVELOPED - 11 segments of dsRNA
41
what are some (4) viral causes of non inflammatory diarrhea?
- norovirus - rotavirus - adenovirus - astrovirus ALL ARE NAKED VIRUSES