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Flashcards in L79 Deck (34):
1

What disease does rhinovirus cause? Transmission?

The common cold is transmitted by resp droplets

2

What are unique replication requirements of rhinovirus?

Prefers the cold
Nose > lungs

3

Why does rhinovirus make asthma worse?

Turns on Th2 response

4

Describe the rhinovirus genome - what is unique?

IRES = internal ribosome entry site
- Ribosome knows to start here, don't need to scan the genome for start codon
Means rhinovirus RNA genome doesn't need to be capped like human RNA does

5

Rhinovirus pathogenesis - how does it change host cell processes? Where in the host cell does it replicate?

Infects nasal epithelium
Shuts off all host translation to push viral translation - preferential replication
RNA genome = replicate in cytoplasm

6

How does rhinovirus leave host cells

Lysis

7

Describe the timeframe of rhinovirus cold - what immunity is responsible for clearing the cold?

0 = infected
Day 2 = viral peak in serum
Day 3-4 = symptom peak
Day 5 = virus gone from serum
Innate immunity clears - entire infection moves too fast for Ab to be produced/effective

8

Why isn't there a rhinovirus vaccine?

Too many strains - recombination

9

What bug causes flu?

Orthomyxoviridae

10

Orthomyxoviridae genetics:
- or +
ss or ds
Helical or icosahedral capsid
Enveloped?

-ssRNA in 8 indep segments
Helical
Enveloped

11

Where does Orthomyxoviridae replicate in host cells?

Nucleus

12

Which proteins are present on Orthomyxoviridae envelope?

HA
NA

13

Describe flu nomenclature:
A/California/07/2001 (H1N1)

A = type of flu (A, B or C)
Cali = where first isolated
07 = isolate #
2001 = year of isolation
H1N1 = major HA & NA type

14

What receptor does flu bind to enter host cells?

HA + sialic acid

15

How is the flu genome release after being endocytosed?

Endosome turns ACIDIC via M2 channel
HA triggered virus/endosome membrane fusion
Release genetic material alone

16

How does Orthomyxoviridae leave host cells?

Bud off

17

How does Tamiflu work?

Neurominidase inhibitor
Block the release of new virions

18

How does flu effect ciliated epithelium?

Kills them
No cilia - mucus isn't moving to clear infection

19

What is antigenic drift?

Minor HA & HA variations year to year
Due to mistakes made by RNA pol

20

What is antigenic shift?

If 2 flu viruses infect a person at the same time, the virus that buds out has a combo the RNA genomes of both
Genetic reassortment

21

Pandemic: antigenic shift or drift?

Shift = pandemic

22

Epidemic: antigenic shift or drift?

Drift = epidemic

23

What aspect of Orthomyxoviridae would a universal flu vaccine target?

HA

24

Which bugs fall under the umbrella of Paramyxoviridae? Which diseases do they cause?

RSV - pna & bronchiolits
Parainfluenza - croup
Mumps
Measles

25

Paramyxoviridae
- or + RNA
Helical or icosahedral capsid?
Enveloped?

All have -ssRNA -> has viral RNA pol to transcribe viral genome on own
Helical
Enveloped

26

2 major proteins on Paramyxoviridae envelope - describe the fxn of both

HN = binds sialic acid on ciliated epithelial cells
F protein = fusion
*Must be at NEUTRAL pH

27

Which parainflu serotypes cause croup? What is croup?

Serotypes 1-3
Croup = distinct barking cough

28

Which parainflu serotype causes bronchiolitis?

4

29

How does Paramyxoviridae leave host cells?

Budding
Therefore envelope is derived from host cell membrane

30

Where in the host cell does viral replication and assembly take place for Paramyxoviridae?

RNA virus --> cytoplasm
1. Uncoat genome
2. Viral RNA transcribed
3. +sense amde
4. Viral proteins through ER/Golgi --> surface
5. RNA to PM site --> budding

31

How does Paramyxoviridae interact with host immunity?

Inhibits innate immunity
Cells cant fight the infection against them --> increases spread

32

Parainflu transmission

P2P - small infectious dose

33

What 2 diseases does RSV cause?

Pediatrics:
Pna
Bronchiolitis

34

Why do you know human metapneumo?

Causes diseases that look a lot like RSV - less severe