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MIIM20002 - Microbes, Infections, Responses > Lecture 18 - Emerging Viral Disease > Flashcards

Lecture 18 - Emerging Viral Disease Flashcards

(49 cards)

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1
Q

What is an emerging viral disease?

A
  • Newly appeared

OR

  • Previously existed, but rapidly increase in incidence or geographical range
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2
Q

What is an emerging viral disease?

A
  • Newly appeared

OR

  • Previously existed, but rapidly increase in incidence or geographical range
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3
Q

What are some examples of emerging viral disease?

A

SARS-CoV
HIV
Ebola

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4
Q

What are some factors that lead to the emergence of new disease?

A
  • Mutation rate of viruses
  • Ecological changes
  • Human demographics and behaviour
  • Air travel
  • Technology and industry
  • Public health measures
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5
Q

Most emerging viral diseases are…

A

Zoonoses

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6
Q

What are some examples of zoonoses?

A

Birds: influenza
Monkeys: HIV
Bats: SARS-CoV

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7
Q

What does SARS stand for?

A

Severe acute respiratory syndrome

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8
Q

Describe what happened in the SARS epidemic

A 
2003
First cases in China
Spread to 32 countries
800 people died
$20 billion
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9
Q

What are the symptoms of SARS?

A

Fever
Cough
Shortness of breath
Chest X ray –> pneumonia

+ + exposure to SARS patient

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10
Q

How was SARS transmitted?

A

Person - person

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11
Q

What are some examples of emerging viral disease?

A

SARS-CoV
HIV
Ebola

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12
Q

What are some factors that lead to the emergence of new disease?

A
  • Mutation rate of viruses
  • Ecological changes
  • Human demographics and behaviour
  • Air travel
  • Technology and industry
  • Public health measures
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13
Q

Most emerging viral diseases are…

A

Zoonoses

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14
Q

What are some examples of zoonoses?

A

Birds: influenza
Monkeys: HIV
Bats: SARS-CoV

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15
Q

What does SARS stand for?

A

Severe acute respiratory syndrome

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16
Q

Describe what happened in the SARS epidemic

A 
2003
First cases in China
Spread to 32 countries
800 people died
$20 billion
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17
Q

What are the symptoms of SARS?

A

Fever
Cough
Shortness of breath
Chest X ray –> pneumonia

+ + exposure to SARS patient

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18
Q

How was SARS transmitted?

A

Person - person

Airbone droplets from sneezing

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19
Q

What was interesting about the spread of SARS?

A

20% of cases were Health Care workers –> defied normal control measures

Superspreaders: some people spread the virus to a huge number of people

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20
Q

What type of virus is SARS?

21
Q

What is the natural host of SARS?

What other animal was a host to a similar corona virus?

Study These Flashcards
A

Bats

Civit cat

22
Q

Which subtypes of influenza are endemic in man?

Study These Flashcards
A

Type A:
H1N1
H3N2

23
Q

Which cells in man are infected by influenza?
How about in birds?

What is the significance of this?

Study These Flashcards
A

Humans: Cells bearing SA a2-6 Galactose

Birds: cells bearing SA a2-3 Gal

Normally prevents avian viruses from infecting man

24
Q

What happens when the aviacn virus infects man?

Why?

Study These Flashcards
A

Pandemic

Because no one has any antibody to the new subtype

25
How is antigenic shift different from antigenic drift? Describe antigenic shift
Shift: • bigger change in a shorter period of time • two different strains / subtypes coming together • mixture of surface antigens
26
What is the cause of a pandemic?
Antigenic shift This is when there is suddenly a new subtype that can infect man
27
What were the influenza pandemics seen in the 20th century?
Spanish flu: H1N1 Asian flu: H2N2 Hong Kong flu: H3N2
28
What happens to the existing subtype when there is a pandemic?
The old subtype is replaced. eg. H3N? --> H1N1 in Spanish flu
29
How do new human subtypes come about?
Antigenic shift Mechanism: • Reassorment • direct invasion with avian strain, then mutation
30
Describe what happened in the Spanish flu pandemic?
25-30% population infected 50 million deaths 15-30 yo mainly affected During WWI
31
What were the symptoms of Spanish flu?
Pulmonary oedema Haemorrhage Cyanosis (purple lips)
32
Why was the H1N1 of the Spanish flu so lethal?
Don't know yet, but sequences are currently being studied by Reverse genetics
33
What is the subtype of Avian influenza?
H5N1 HPAI (Highly pathogenic avian influenza)
34
What happens to birds that are infected with H5N1 HPAI?
Infects systemically and rapidly brings death
35
Does H5N1 infect man?
Yes --> lethal However, it can not be spread from Human-Human
36
How can HPAI infect systemically?
The cleavage site on HA has mutated It can now be cut by an enzyme found all over the body
37
What is the potential route for an H5N1 pandemic?
1. Mutation --> Becomes virulent to poultry 2. Infects man directly with low efficiency 3. Antigenic drift, so that it affects man with high effiency PANDEMIC
38
In 1997, there were 20 cases of Avian flu in man. How was the epidemic halted?
Culling of poultry
39
What is the fatality rate of avian flu? | How does this compare to seasonal epidemic influenza?
H5N1: 60% Seasonal epidemic influenza: 0.01%
40
Which drugs are effective against avian flu?
NA inhibitors
41
Describe the process of reassortment?
In a 'mixing vessel' • Pig cells have surface receptors that allow invasion by both human and avian influenza • Single cell infected with both strains at once • reassortment • New strain: - human internal proteins - avian HA and NA
42
What does reassortment bring about?
Antigenic shift
43
Describe the origin of the 2009 H1N1 pandemic?
1918 H1N1 in North America + Swine viral genes 2009 Pandemic H1N1
44
Describe the infection caused by 2009 H1N1 Swine flu
``` Same as seasonal influenza: • fever • cough • muscle pains • malaise • fatigue ``` NB not systemic
45
Compare lethality of Swine flu, Avain flu and seasonal influenza
Avian flu is highly lethal Both Swine flu and seasonal influenza aren't very lethal, unless the individual is immunosuppressed
46
Compare replicative ability of seasonal flu and swine flu
Swine flu has a greater ability to replicate in lungs Younger people are getting viral pneumonia
47
How is Swine flu treated?
NA inhibitors
48
Can we make vaccines against H5N1 now for when it becomes a pandemic?
Yes, but they probably wouldn't be effective due to antigenic drift
49
How can we treat H5N1 if it becomes a pandemic?
NA inhibitors | However, we won't be able to produce enough

MIIM20002 - Microbes, Infections, Responses (32 decks)

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