30- Coronavirus

Question 1

traits of microorganism causing coronavirus

Answer 1

• called coronaviridae
• enveloped, helical capsid positive ssRNA
• one of the largest RNA viruses
• is widely present in the animal world

Question 2

why is it called coronavirus

Answer 2

for the corona like halo formed by their envelopes and glycoproteins spikes

Question 3

how is coronavirus transmitted

Answer 3

via large droplets from the upper respiratory tract, it replicates in epithelial cells here

Question 4

what are the top 2 most common etiologies of colds

Answer 4

rhinovirus

coronavirus

Question 5

T/F the SARS-Cov2 genome sequence shared 80% sequence identity with SARS-Cov and 50% with MERS-Cov

Answer 5

T

Question 6

cross species transmission of sars-cov involved which species

Answer 6

reservoir: horseshoe bats
intermediate/amplicfication host: civets
humans

Question 7

cross species transmission of mers-cov

Answer 7

reservoir: bats
intermediate host: camelids
humans

Question 8

SARS-Cov2 uses the SARS-Cov receptor called ? which is expressed on ?

Answer 8

• ACE2
• on type 2 alveolar cells (AT2)

The spike protein of sars cov 2 is primed by TMPRSS2 (allows fusion of viral and cellular membranes)

Question 9

What are the 3 methods of entry of animal viruses

Answer 9

• direct penetration: Where the viral capsid attaches and sinks into the cytoplasmic membrane creating a pore through which the genome enters the cells (POLIOVIRUS)
• membrane fusion: viral envelope and the host cell membrane fuse and the capsid is released inside the cell (MEASLES, CORONAVIRUS)
• endocytosis: is of naked viruses or enveloped viruses (ADENOVIRUS, HERPESVIRUS, CORONAVIRUS)

Question 10

SARS-COV2 life cycle

Answer 10

1. binding: spike protein to ACE2
2. entry: cleavage of S1/S2 by TMPRSS2 or endolysosomal cathepsin L
3. RNA genome is released and translated
4. replication
5. positive strand genome serves as a template for full lenght negative strand RNA and subgenomic RNA
6. structural proteins and accessory proteins are inserted into ER-GOLGI for virion assembly
7. more positive sense RNA genomes are incorporated into newly synthesized virions

Question 11

Stages of sars-cov2 and covid 19

Answer 11

stage 1: Active viral infection (dry cough, fever, fatigue)
stage 2: hypoxemia, impending resp failure
stage 3: dysregulated lung and systemic inflammation (ARDS, multiorgan failure, death)

Question 12

Current covid 19 neurological dx mechanisms

Answer 12

systemic inflammatory response

• vascular leakage
• prothrombotic state
• direct viral invasion
• activation of astrocytes and microglia
• infiltration of cytotoxic T cells

Question 13

DX of sars-cov2

Answer 13

molecular detection with RT-PCR

- or they detect ORF1b, N, E, or S genes

Question 14

sars cov2 serological tests detect which abs

Answer 14

antibodies to N or S protein

- note that these can be used to assess response to vaccines

Question 15

How does the rapid antigen (immunochromatographic dipstick) test work?

Answer 15

the dipstick is coated with colloidal metal particles linked to movable antibodies (against one antigen) at one end and anti-antibodies fixed in a line at the other end

• you put the stick in the pts antigen sample
• watch movement of fluid with ab-antigen up the stick
• the anti-antibodies stop the movement and the color becomes visible due to the density of the complexes