Infectious Disease 4: Covid 19

Question 1

Describe the spread and epidemiology of COVID-19
- Dec 31 2019: (?)
- Jan 7 2020: (?)
- Jan 10 2020 (?)
- Jan 11 2020 (?)
- Jan 21 2020
- Jan 23 2020
- Jan 25 2020

Answer 1

• Dec 31 2019: first announcement from Wuhan
• Jan 7 2020: Cause identified as a new coronavirus
• Jan 10 2020: Unofficial genome sequence released
• Jan 11 2020: China reports first known death
• Jan 21 2020: First US case
• Jan 23 2020: Wuhan placed under quarantine
• Jan 25 2020: First canadian case

Question 2

Difference between SARS-CoV-2 and Covid-19

Answer 2

SARS-CoV-2: severe acute respiratory syndrome coronavirus 2 (the Virus)
Covid-19: illness caused by SARS-CoV-2 infections )the Disease)

Question 3

Coronavirus spread: By Feb 28 2020 there were (?) cases in (?) countries

Answer 3

Coronavirus spread: By Feb 28 2020 there were 83652 cases in 52 countries (most in china)

Question 4

Describe the virology and classification of SARS-CoV-2:
- Family?
- Size?
- Presence of envelope?
- Shape?
- Genome?

Answer 4

• Belongs to the Coronaviridae family of viruses
• Enveloped, 60-140nm in diameter
• Helical capsid inside envelope
• Positive sense, single-stranded RNA genome
• Genome is ~30kb in length

Question 5

• Describe the transmission of COVID-19

Answer 5

• Animal to human spread is the initial transmission event
• Person-to-person = current transmission
• Routes of transmission:
  Respiratory Droplets
  Airborne
  Contaminated hands and surfaces

Question 6

Describe the main clinical features of Covid-19
1. Incubation period
2. Common symptoms
3. Fairly common symptoms
4. Less common symptoms
5. Severity

Answer 6

1. Incubation period: 2-14 Days (usually 4-5)
2. Common symptoms:
   fever/chills
   cough
   SoB
   muscle aches
   headaches
3. Fairly common symptoms
   sore throat; diarrhea; nausea/vomiting
4. Less common symptoms
   runny nose, abdominal pain, loss of smell/taste
5. Severity: infections can be asymptomatic, mild, severe or critical

Question 7

Covid 19 complications:

Answer 7

• Pneumonia and respiratory failure
• Heat issues including rhythm problems, shock, heart injury
• Abnormal blood clot formation in the lungs and brain
• Inflammatory “over-activation” (cytokines)

Question 8

• Describe the different diagnostic modalities (5) for COVID-19

Answer 8

• Culture (research)
• Electron Microscopy (research)
• Nucleic acid detection
• Antigen Detection
• Serology

Question 9

Describe the different diagnostic modalities (5) for COVID-19
SARS-CoV-2 Culture
- culture process
- Observations if positive

Answer 9

• Samples suspected of containing virus inoculated onto Vero cells (kidney epithelial cell line) containing anitmicrobials to kill contaminating microflora
• Incubated at 37C in 5%CO2 for up to 8days
• IF POSITIVE: observe cytopathic effect (cells changing shape, arrangement, and dying)

Question 10

Advantages & disadvantages of SARS-CoV-2 culture

Answer 10

Advantages: Can be used to produce more virus, doesn’t require special equipment
Disadvantages: labor intense; requires expertise; takes a long time; effects could be caused by a different virus (ie non-specific, would have to do a confirmatory test)

Question 11

Describe electron microscopy for COVID-19
- when is it used
- Diagnostic element
- Disadvantages

Answer 11

• Not typically used anymore for routine viral diagnostics but helpful in virus discovery
• Distinctive Spikes arorund the edge of the virus envelope
• Impractical, costly, laborious

Question 12

Describe NATs for SARS-CoV-2:
- Sensitivity/specificity
- Cost
- Time to results
- Done using:

Answer 12

Current gold standard in Cov-19 diagnostics
- Extremely analytically sensitive and specific
- Cost - ranges
- Time to results: quickly (minutes to hours)
- Done using: Nucleic acid extraction machines and PCR cyclers

Question 13

• Describe drugs and vaccines used for COVID-19

Answer 13

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