Micro - Coronavirus

Question 1

CoV is (enveloped, nonenveloped) (segmented, nonsegmented) (RNA+, RNA-, DNA)

Answer 1

Eveloped segmented RNA+

Question 2

Two main organ systems affected by CoV

Answer 2

Respiratory + GI

Question 3

What is unique about CoV genome?

Answer 3

Largest known RNA genome to date

Question 4

Characteristic of all RNA+ genomes

Answer 4

Don’t have own RNA polymerase although their genome codes for it

Question 5

CoV genome resembles ___ b/c:

Answer 5

Eukaryotic mRNA

Has 5’methyl cap and 3’ PolyA tail

Question 6

Two major diseases caused by CoV

Answer 6

Common cold

SARS

Question 7

How to treat common cold caused by CoV

Answer 7

Don’t – self-limited

Question 8

Pathophys of SARS-CoV infection

Answer 8

Infects type II pneumocytes causing diffuse alveolar damage and ARDS

Question 9

First sx of SARS

Answer 9

Fever

Question 10

Describe progression of SARS sx

Answer 10

Fever
Flu-like sx for 2-7 days
Hypoxemia, dyspnea, dry cough at 3-7 days
Respiratory failure +/- GI sx with lymphopenia

Question 11

Incubation period for SARS-CoV

Answer 11

2-10 days

Question 12

Transmission of SARS-CoV

Answer 12

Human-to-human via droplets
Contaminated surfaces
Fecal

Question 13

Virulence factors of CoV

Answer 13

1. S (spike) protein
2. HE (hemagg-esterase)
3. E (envelope) protein
4. M (membrane) protein
5. N (nucleocapsid) protein
6. RdRp (RNA-dependent RNA polymerase)
7. PL-pro (papain-like protease)
8. 3CL-pro (3C-like protease)

Question 14

How does S (spike) protein contribute to CoV virulence?

Answer 14

Aids in attachment and viral membrane + host membrane fusion

like F protein of paramyxoviruses

Question 15

How does HE protein contribute to CoV virulence?

Answer 15

Aids in viral entry and exit

Question 16

How does E protein contribute to CoV virulence?

Answer 16

Integral part of viral membrane involved in morphogenesis, assembly, budding, and has an ion channel important in replication

Question 17

How does M protein contribute to CoV virulence?

Answer 17

Budding + part of envelope

Question 18

How does N protein contribute to CoV virulence?

Answer 18

Binds to viral genome + M protein and assists in assembly and budding

Question 19

How does RdRp contribute to CoV virulence?

Answer 19

It doesn’t proofread, so allows a lot of variation

Question 20

How do PL-pro and 3CL-pro contribute to CoV virulence?

Answer 20

Cleave immature viral polypeptides into mature viral proteins

Question 21

Steps in RNA+ genome replication

Answer 21

1. Entry and uncoating
2. Transcribe RdRp + PL-pro + 3CL-pro
3. RdRp + PL-pro + 3CL-pro transcribe antigenomic RNAs
4. These RNAs used as templates for transcribing RNA- in a discontinuous fashion
5. RNA- strands serve as templates for transcribing mRNAs
6. mRNAs transcribed into non-replicase proteins

Question 22

Two ways in which CoV can produce variable genomes

Answer 22

1. High error rate of RdRp

2. Reassortment (remember: CoV genome is segmented) when two strains infect same cell

Question 23

Seasonality of CoV

Answer 23

Winter-spring

same as influenza and hPIV3

Question 24

Who gets pneumonia due to CoV?

Answer 24

Infants, elderly, immunocompromised

Question 25

Who gets GI infection due to CoV?

Answer 25

Infants < 1 year

Question 26

SARS-CoV was transmitted to humans via:

Answer 26

Bats

Question 27

Who is most likely to get a CoV infection and when?

Answer 27

Children in winter

Question 28

What history on top of respiratory symptoms might suggest SARS-CoV?

Answer 28

Recent travel to China, Taiwan