Rotavirus, Norovirus, and Enteroviruses Flashcards Preview

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Flashcards in Rotavirus, Norovirus, and Enteroviruses Deck (41)
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1

Rotavirus is the single most important etiologic agent of severe diarrheal illness in what age group, worldwide?

Infants and young children

2

Rotavirus is a Reoviridae, what does Reo mean?

Resipiratory, enteric, orphan

3

Describe the structure of Rotavirus.

Non-enveloped (2-3 concentric icosahedral capsids), segmented, dsRNA genome with high antigenic diversity

4

Describe the antigenic diversity of rotavirus and why it is important.

It is divided into 11G (VP7) and 12P (VP4) serotypes; However only 4 G-P combinations cause about 90% of disease in humans = the reason we can have a vaccine!

5

The rotavirus is taken in by endocytosis and delivered to late endosomes or lysosomes, what happens here?

Capsid proteins are proteolytically processed --> generates infectious sub viral particle (this can occur outside cells or following endocytosis in late endosomes/lysosomes

6

After rotavirus penetrates, what happens?

Enzymes within the core begin synthesizing mRNA's; transcription is asymmetric so only individual + strands mRNAs are made

7

After + strands of mRNA are made what happens?

Some of the capped mRNAs are assembled into assortment complexes, the capped + strands also serve as templates for synthesis of the complementary - strands --> produces dsRNA

8

Assembly of the rotavirus occurs where?

Within the cytoplasm; released by lysis of the cell

9

Noroviruses (Calciviridae) cause what?

Major cause of food borne epidemic acute gastroenteritis in older children and adults

10

What is the replication scheme for Noroviruses hypothesized to be similar to? What is their structure?

Picornavirus; Nonenveloped, non segmented, + strand RNA

11

True or False: Rotavirus causes diarrhea primarily in the elderly and is responsible for 35-50% of diarrheal hospitalization during the last two years of life.

False; in the young and first two years of life

12

True or False: Norovirus are responsible for 50% of community-based outbreaks of nonbacterial gastroenteritis in school aged children and adults.

True - known as "winter vomiting disease"

13

How are rotavirus and norovirus transmitted?

Fecal-Oral route

14

Why are rota and noro stable in the environment?

No envelopes!

15

Norovirus outbreaks are often linked to what?

A single source; contaminated food or water (think raw or steamed shellfish, cake frosting, and salads or cruise ship outbreaks)

16

What do the clinical symptoms for rota and noro consist of?

N/V, diarrhea, fever, dehydration

17

What do both rota and noro initially infect? How do they differ from V. Cholera?

Initially infect villous epithelium of SI which leads to functional alteration in the SI. Glucose-coupled sodium transept is impaired but adenylate cyclase and cAMP are NOT stimulated

18

Why are deaths from rota and noro so rare in the US?

Availability of effective fluid and electrolyte replacements

19

What is most important for protection of reinfection by rota and noro?

Local (intestinal) immunity

20

Describe how antibodies to rota and noro are formed.

Ab to rota are obtained relatively early in life; ab to noro are acquired gradually and increase steadily over a person's lifetime

21

Why is there a vaccine for rota and not for noro?

There are only 4 major serotypes of rota that cause the disease which makes a disease practical even in the face of antigenic shift and drift; noro immunity is not long lasting and diversity is generated via antigenic drift like other ssRNA viruses

22

What is Rotateq?

A pentavalent bovine-human reassortant virus covering G1-G4 and P8 (live attenuated and orally in 3 doses at 2, 4, 6 mo.)

23

What is Rotarix?

Human derived monovalent (G1, P8) live attenuated vaccine (given orally in 2 doses starting at 6 weeks)

24

How do you prevent norovirus?

Careful hand washing, effective disinfection of contaminated surfaces, proper food prep

25

What are the general characteristics of Enteroviruses?

Small, non enveloped, + strand RNA

26

What does Picorna mean and what should it help you remember?

pica + RNA (Small RNA); picor = polio, insensitive to ether (non enveloped), coxsackie, orphan virus, rhinovirus

27

What does poliovirus cause?

flaccid paralysis

28

What does Coxsackie cause?

various illnesses including meningoencephalitis, diarrhea, muscle pain, inflammation of myocardium and pericardium

29

What do echoviruses and other viruses cause?

Mild gastroenteritis (echo = enteric cytopathic human orphan)

30

What is hepatitis A?

An enterovirus-like picornavirus