CoronaVirus Flashcards
Where did the sars cov 1 started
in china and then it spreaded
how was sars cov 1 transmitted
Droplet infection, aerosolization, fomites, contaminated stool
clinical symptoms od sars cov 1
- 2-10 day incubation period (contagious)
- Lower respiratory tract illness (viral pneumonitis)
- Fever, myalgia, malaise, chills, dry cough, shortness of breath, lymphopenia, decreased platelet counts, prolonged coagulation, elevated hepatic enzymes
- 10-20% require mechanical ventilation
who got the most killed by the of covid
old people
How was the og covid first descrived as
infectious atypical pneumonia
How did they realized what the og covid was
etiological agent was identified as a new coronavirus not previously endemic to humans
Where the mers comes from
saudi arabia
which country in asia did mers get to
korea
epidemiological investigation regarding mers showed that?
-mers is circulating in dromedary camels as early as 1933
-subssequently isolated from bats
true or false: in mers, secondary infection is worse than the first
false, the first is worse than the second
what are super spreaders
- host that is infected with a disease that infects more secondary contacts than other hosts who are also infected with the same disease
-they may not show any symptoms of the disease
-high concern in epidemiology
what is the rule in epidemiology for the spread ld virus
20% of infected people infect 80% of the people that get infected
what can limit pathogen spread
-early diagnosis
-early discovery
-early intervention
-quarantine
failure of any of these factors can lead to prolonged and sustained pathogen transmission
What is the basic reproduction Number aka R0
-# of cases one case generates on average over the course of its infectious period, in an otherwise uninfected population
-When R0 < 1, infection will die out in the long run
-But, when R0 > 1, the infection will be able to spread in a population
True or false: the lower the R value is the harder it is to deal with the virus
false
the higher the R value is, the harder it is to deal with the virus
facts about coronavirus fam
*Due to the appearance under electron microscopy of the viral spike peplomers
-Enveloped viruses Coiled helical capsid
-120-160 nm in diameter Genome: (+) ssRNA
-Monopartite, linear
-27-32 kb in length!
which virus is the largest rna virus
covid
what can coronavirus cause
-respiratory illnesses in humans
-important vetenary disease: peritonitis, pneumonia, gastroenteritis and hepatitis
-30% of common colds in humans
-may cause gastroenterisis and encephalitis rarely
is there treatments for coronaviruses
no
does coronaviruses contain any cap or poly a tail
it has a cap and a tail
which end encodes for a poly protein in the coronavirus fam
the 5’ end
-proteolytically cleaved to generate non structural proteins: nsp
what what does the 3’ end in coronaviruses encode for
-four structural proteins
-spike (s)
-membrane (M)
-envelipe (E)
-nucleocapsid (N)
-accessory proteins -unique to each virus species
which protein of covid binds to the host cell
spike
cellular entry of covid
- SARS binds to Angiotensin Converting enzyme 2 (ACE2) and L- SIGN (a lectin)
- The virus envelope fuses with the plasma membrane or an endosomal membrane
- Spike protein(s) mediate attachment and fusion
Polyprotein processing with covid
-the replicase gene is directly translated from genomic rna into viral polyproteins(pp1a and pp1ab)
-comprised of orf1a and orf1b
-ribosomes translating orf1a can pause at a pseudoknot and frameshift allowing translation of orf1b
nsp’s are responsible for what in covid
Nsps are responsible for:
* Polyprotein processing
- Proteases
* RNA replication
- RNA-dependent RNA polymerase
- RNA helicase
- Replication complex
formation
- RNA cap formation
- RNA modifying enzymes
what does nsp14 do in covid
it is the proofreading proteins=less mutations
true or false: replication complexes are associated with nucleus membrane in covid
false, it is cytoplasmic
Covid replication complexes
Replication complexes are the sites of viral RNA synthesis
* Altered membrane structures are virally-induced
* Reticulovesicular network of modified membranes
* Modifications include: double membrane vesicles (DMVs), vesicle packets (VPs), and convoluted membranes (CMs)
* Encapsidation (packaging) also occurs at these sites
does covid uses continuous or discontinuous translation?
discontinuous translation
in covid: non-replicase proteins are expressed from…..
-non-replicase proteins are expressed from nested subgenomic mrna
Base-pairing of the Transcriptional Regulatory Sequences (TRS) results in
Base-pairing of the Transcriptional Regulatory Sequences (TRS) results in discontinuous transcription of minus-sense subgenomic RNAs that give rise to a ‘nested’ set of mRNAs
Nested subgenomic mRNAs have common …
3’ ends and 5’ leader sequences (encoded at the 5’ end of the genomic RNA)
viral packaging, assembly and release of covdi
-Encapsidation (packaging) and budding occurs on altered cellular membranes
burst
-ER-Golgi Intermediate Compartment (ERGIC)
* Virions are released from the
cell by exocytosis of secretory vesicles
Evolution of coronaviruses
- Subtle changes (e.g. in the Spike protein) can alter tissue tropism,
-host range, and pathogenicity Changes occur by:
High error rate of the coronavirus RNA polymerase
RNA-RNA recombination events (arising from discontinuous transcription)
true or false: we were lucky with covid
true, we were
(SARS-CoV-1 R0 = 2.7; IAV = 5-25)
