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Flashcards in L79 Deck (34)
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1
Q

What disease does rhinovirus cause? Transmission?

A

The common cold is transmitted by resp droplets

2
Q

What are unique replication requirements of rhinovirus?

A

Prefers the cold

Nose > lungs

3
Q

Why does rhinovirus make asthma worse?

A

Turns on Th2 response

4
Q

Describe the rhinovirus genome - what is unique?

A

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
Q

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

A

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

6
Q

How does rhinovirus leave host cells

A

Lysis

7
Q

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

A
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
Q

Why isn’t there a rhinovirus vaccine?

A

Too many strains - recombination

9
Q

What bug causes flu?

A

Orthomyxoviridae

10
Q
Orthomyxoviridae genetics:
- or + 
ss or ds 
Helical or icosahedral capsid
Enveloped?
A

-ssRNA in 8 indep segments
Helical
Enveloped

11
Q

Where does Orthomyxoviridae replicate in host cells?

A

Nucleus

12
Q

Which proteins are present on Orthomyxoviridae envelope?

A

HA

NA

13
Q

Describe flu nomenclature:

A/California/07/2001 (H1N1)

A
A = type of flu (A, B or C)
Cali = where first isolated
07 = isolate #
2001 = year of isolation 
H1N1 = major HA & NA type
14
Q

What receptor does flu bind to enter host cells?

A

HA + sialic acid

15
Q

How is the flu genome release after being endocytosed?

A

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

16
Q

How does Orthomyxoviridae leave host cells?

A

Bud off

17
Q

How does Tamiflu work?

A

Neurominidase inhibitor

Block the release of new virions

18
Q

How does flu effect ciliated epithelium?

A

Kills them

No cilia - mucus isn’t moving to clear infection

19
Q

What is antigenic drift?

A

Minor HA & HA variations year to year

Due to mistakes made by RNA pol

20
Q

What is antigenic shift?

A

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
Q

Pandemic: antigenic shift or drift?

A

Shift = pandemic

22
Q

Epidemic: antigenic shift or drift?

A

Drift = epidemic

23
Q

What aspect of Orthomyxoviridae would a universal flu vaccine target?

A

HA

24
Q

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

A

RSV - pna & bronchiolits
Parainfluenza - croup
Mumps
Measles

25
Q

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

A

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

26
Q

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

A

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

27
Q

Which parainflu serotypes cause croup? What is croup?

A

Serotypes 1-3

Croup = distinct barking cough

28
Q

Which parainflu serotype causes bronchiolitis?

A

4

29
Q

How does Paramyxoviridae leave host cells?

A

Budding

Therefore envelope is derived from host cell membrane

30
Q

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

A

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
Q

How does Paramyxoviridae interact with host immunity?

A

Inhibits innate immunity

Cells cant fight the infection against them –> increases spread

32
Q

Parainflu transmission

A

P2P - small infectious dose

33
Q

What 2 diseases does RSV cause?

A

Pediatrics:
Pna
Bronchiolitis

34
Q

Why do you know human metapneumo?

A

Causes diseases that look a lot like RSV - less severe