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AFNS 416 > 16 - Coronaviruses > Flashcards

16 - Coronaviruses Flashcards

1
Q

Four genera of coronaviruses

A
  • alphacoronavirus
  • betacoronavirus
  • deltacoronavirus
  • gammacoronavirus
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2
Q

Important coronaviruses & their genera

A
  • Porcine epidemic diarrhea virus (alpha)
  • Severe acute respiratory syndrome CoV (SARS-CoV) (beta)
  • Middle East respiratory syndrome CoV (MERS-CoV) (beta)
  • SARS-CoV-2 (beta)
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3
Q

Subgenus of betacoronaviruses, animal reservoir, routes of human infection

A

Sarbecoviruses

Bats (rhinolocus or horseshoe bats) ~ 100 spp

2 routes:
- direct contact w bats
- contact w mammalian species infected w virus (e.g. civet cats, camel)

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4
Q

Coronavirus genome?

A

Enveloped positive-strand RNA viruses
30-32 kb

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5
Q

Outbreak, symptoms and risk group of SARS

A

2003 in Guangdong China
Symptoms: headache, fever, dry cough, sore throat, shortness of breath
Risk group: >60 years old, other conditions

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6
Q

Transmission, intermediate host of SARS. Status?

A

Person to person
Droplets from sneezing, touching contaminated surfaces

Civet cats intermediate hosts

Last case in late 2003, extinct in humans

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7
Q

infected, fatality rate of SARS

A

> 8000 infected
774 deaths
9.5% fatatlity

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8
Q

MERS-CoV outbreak, what is it? Symptoms? Fatality rate? R0?

A

2012, still circulating

Respiratory disease in middle east

Symptoms: fever, cough, breathing difficulties, vomiting

34% fatality rate
R0 = 2-5

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9
Q

Similarities and differences between SARS and MERS

A

Both originated in bats

SARS = bats to civet cats to humans
MERS = bats to camels to humans

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10
Q

Zoonotic diseases transmitted by bats

A
  • rabies
  • histoplasmosis
  • marburg hemorrhagic fever
  • Nipah
  • SARS
  • Ebola
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11
Q

What is the bat virome

A

19 families of mammalian viruses identified in analysis of 40 bat species in China

Large majority were coronaviruses

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12
Q

What makes bats dangerous hosts

A

They harbor viruses with few clinical signs of disease

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13
Q

Describe the 1918 H1N1 PANDEMIC

A

Spanish flu
500 x 10^6 infected
~50 million deaths worldwide
Affected young adults
Life expectancy declined by 10 years in US

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14
Q

Origins of Spanish Flu

A

Likely not Spain
During WW1. media censored news about flu. Except in Spain, where cases (infection, dead) were reported and publicized

Origin(s) unclear: US? Britain? China?

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15
Q

H1N1 deaths in Canada

A

30,000-50,000

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16
Q

Spanish flu response difference in Philadelphia vs St Louis

A

Philly: Did not take action for 2 weeks after first case, had a city-wide parade. Numbers were high

St Louis: closed theatres, schools, banned public gatherings two days after first case. Numbers were low

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17
Q

What is ProMED

A

Program for Monitoring Emerging Diseases

Largest publicly available system providing global reporting on infectious disease outbreaks (measles, dengue, zika, FMD, COVID)

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18
Q

Where do we speculate COVID-19 originated

A

Wuhan, China in a market selling wild animals or a lab escape from Wuhan Institute of Virology (CoV research)

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19
Q

What are raccoon dogs

A

Relative of foxes, susceptible to SARS CoV 2
Intermediate host for CoV 19

20
Q

COVID-19 virus

A

Severe Acute Respiratory Syndrome Coronavirus 2

21
Q

COVID-19 symptoms

A
  • fever or chills
  • cough
  • difficulty breathing
  • fatigue
  • body aches
  • headache
  • loss of taste or smell
  • sore throat
  • congestion
22
Q

What is PCC?

A

Post-COVID conditions (long-covid)

Occurring in individuals with a history of probable or confirmed SARS-CoV-2 infection, usually 3 months from onset, with symptoms lasting at least 2 months and not explained by alternative diagnosis

23
Q

Long covid more common in? Management?

A

Individuals that had severe covid
Higher risk if unvaccinated & infected

Supportive care

24
Q

Current covid deaths? In Canada?

A

7 million

58,560

25
Q

How are changing COVID-19 viruses affecting reporting

A

Omicron variants less severe than previous delta variants

Fewer COVID cases being reported
“Living with COVID” disregards immune comp, long covid

26
Q

Human to animal transmission of COVID-19

A

Reverse zoonosis
Not many cases
Dogs, cats, non-human primates, mink, deer

27
Q

Slide 48

A

Reverse zoonosis

28
Q

Danger of reverse zoonosis

A

Likelihood of virus changing when adapting to new host = novel SARS CoV 2 variants in humans

29
Q

What is ACE-2

A

Receptor for SARS-CoV-2
Angiotensin 1 converting enzyme

For virus to enter cell, interaction btw spike protein and ACE2 on outside of cell membrane

30
Q

How did we identify large numbers of animals that could be infected with SARS-CoV-2

A

If they have ACE-2 similar to humans
Identical sequences (non-human primates) or high sequence homology (caribou, WTD)

31
Q

SARS CoV 2 prevalence in white tailed deer

A

~36% of deer in Ohio were positive

Sequence changes were accelerated when virus in WTD

32
Q

What is incubation period? Varies with…

A

Time of infection to first clinical symptoms

Varies with pathogen (influenza=days, rabies=months) and can vary with dose

= preclinical phase

33
Q

What is the latent period? Infectious period?

A

Latent = time of infection to onset of infectiousness

Infectious = time the individual can transit to others (contagious)

34
Q

What is a type A disease?

A

Infectiousness comes before symptoms
Difficult to control; shedding pathogen with no symptoms

Slide 56

35
Q

What is a type B disease?

A

Onset of infectiousness occurs at the time or onset of symptoms or later

Easier to contain than type A

Slide 57, 58

36
Q

What is ‘excess mortality’

A

Number of deaths from all causes above and beyond what we would have expected to see under ‘normal’ conditions

Deaths from COVID not reported (poor testing, existing medical conditions that worsened)

EM = reported deaths - expected deaths

37
Q

Estimates of excess mortality due to COVID

A

18.2 million in one study

14.83 million in another

Slide 63

38
Q

Typical vaccine development timeline (7)

A
  1. Preclinical trials
  2. Phase 1 clinical trials (demonstrate vaccine does no harm)
  3. Phase 2 clinical trials (assess safety & immune response)
  4. Phase 3 clinical trials (efficacy of vaccine, larger cohort)
  5. Regulatory approval process (send to federal gov)
  6. Scaling up vaccine manufacturing
  7. Post-licensure vaccine safety monitoring
39
Q

Why was COVID vaccine development/approval so fast?

A
  • newer technologies (RNA vaccines)
  • governmental funding (guaranteed purchase, bankrolling companies, invested in building manufacturing capacity)
  • bureaucratic changes
40
Q

Three forms of “traditional vaccines”

A
  • Live-attenuated vaccine: weakened form of virus, strong long-lasting immune response
  • Inactivated vaccine: killed virus (heat, chemicals). e.g. rabies
  • Subunit recombinant vaccines: protein subunit.
41
Q

Why don’t mRNA vaccines affect or interact with our DNA

A
  • mRNA never enters nucleus of cell (where DNA is kept)
  • cell breaks down and gets rid of mRNA soon after creating protein
42
Q

% vaccinated in high income vs low income countries

A

High income: 73%
Low income: 32%

43
Q

What is the SARS-CoV-2 mutation rate

A

Average ~2 mutations per month
Slower than influenza and HIV

44
Q

One of the first SARS-CoV-2 mutations

A

Aspartic acid originally at position 614 of spike protein (interacts w ACE-2): Jan 2020

Feb 2020: Glycine at position 614 of spike protein

D614 -> G614
mutation = D614G

Slide 73, 74

45
Q

Dominant strain in early pandemic

A

Delta variant, now seeing more omicron

46
Q

One health approaches to future viromics research

A
  • categorizing sequences is important, but not super functional
  • reverse genetic approaches
  • identify viruses that could initiate another pandemic
  • deal with human-wildlife interface to slow new zoonotic diseases
47
Q

Future of COVID-19

A
  • WHO downgrades pandemic (public emergency -> global threat)
  • long covid
  • new variants
  • reverse zoonoses
  • live with covid phase

AFNS 416 (22 decks)

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