L79

Question 1

What disease does rhinovirus cause? Transmission?

Answer 1

The common cold is transmitted by resp droplets

Question 2

What are unique replication requirements of rhinovirus?

Answer 2

Prefers the cold

Nose > lungs

Question 3

Why does rhinovirus make asthma worse?

Answer 3

Turns on Th2 response

Question 4

Describe the rhinovirus genome - what is unique?

Answer 4

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

Question 5

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

Answer 5

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

Question 6

How does rhinovirus leave host cells

Answer 6

Lysis

Question 7

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

Answer 7

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

Question 8

Why isn’t there a rhinovirus vaccine?

Answer 8

Too many strains - recombination

Question 9

What bug causes flu?

Answer 9

Orthomyxoviridae

Question 10

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

Answer 10

-ssRNA in 8 indep segments
Helical
Enveloped

Question 11

Where does Orthomyxoviridae replicate in host cells?

Answer 11

Nucleus

Question 12

Which proteins are present on Orthomyxoviridae envelope?

Answer 12

HA

NA

Question 13

Describe flu nomenclature:

A/California/07/2001 (H1N1)

Answer 13

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

Question 14

What receptor does flu bind to enter host cells?

Answer 14

HA + sialic acid

Question 15

How is the flu genome release after being endocytosed?

Answer 15

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

Question 16

How does Orthomyxoviridae leave host cells?

Answer 16

Bud off

Question 17

How does Tamiflu work?

Answer 17

Neurominidase inhibitor

Block the release of new virions

Question 18

How does flu effect ciliated epithelium?

Answer 18

Kills them

No cilia - mucus isn’t moving to clear infection

Question 19

What is antigenic drift?

Answer 19

Minor HA & HA variations year to year

Due to mistakes made by RNA pol

Question 20

What is antigenic shift?

Answer 20

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

Question 21

Pandemic: antigenic shift or drift?

Answer 21

Shift = pandemic

Question 22

Epidemic: antigenic shift or drift?

Answer 22

Drift = epidemic

Question 23

What aspect of Orthomyxoviridae would a universal flu vaccine target?

Answer 23

HA

Question 24

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

Answer 24

RSV - pna & bronchiolits
Parainfluenza - croup
Mumps
Measles

Question 25

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

Answer 25

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

Question 26

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

Answer 26

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

Question 27

Which parainflu serotypes cause croup? What is croup?

Answer 27

Serotypes 1-3 | Croup = distinct barking cough

Question 28

Which parainflu serotype causes bronchiolitis?

Answer 28

4

Question 29

How does Paramyxoviridae leave host cells?

Answer 29

Budding | Therefore envelope is derived from host cell membrane

Question 30

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

Answer 30

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

Question 31

How does Paramyxoviridae interact with host immunity?

Answer 31

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

Question 32

Parainflu transmission

Answer 32

P2P - small infectious dose

Question 33

What 2 diseases does RSV cause?

Answer 33

Pediatrics: Pna Bronchiolitis

Question 34

Why do you know human metapneumo?

Answer 34

Causes diseases that look a lot like RSV - less severe