Influenza Flashcards

1
Q

How does chest x-ray look with seasonal flu?

A

normal

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2
Q

how long does acute infection of seasonal flu?

A

7 days, cough lasts a few weeks

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3
Q

at risk groups for seasonal flu?

A

young, old

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4
Q

incubation (days) of seasonal flu?

A

1-5 days

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5
Q

infectiousness of seasonal flu (days)??

A

5-6 days

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6
Q

deaths worldwide from seasonal flu?

A

1/4 to 1/2 MILLION

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7
Q

Influenza binds to what on non-ciliated respiratory epithelium?

A

sialic acid sugar

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8
Q

What kind of linkage on the sialic acid is it to galactose?

A

alpha 2-6

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9
Q

Flu spreads from infection site?

A

Nope. Localized.

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10
Q

Which airways does influenza like to replicate?

A

larger airways

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11
Q

what cytokine causes malaise, head and muscular aches?

A

IFNs

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12
Q

What cytokine causes fever?

A

IL-1

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13
Q

where is ciliated epithelium in respiratory system?

A

trachea and bronchi

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14
Q

Do you normally get viral pneumonia with flu?

A

Nope, usually due to secondary bacterial infections after cilia destruction

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15
Q

Influenza have envelopes?

A

Yes

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16
Q

Influenza and Rotavirus has what kind of genome?

A

single stranded -ve sense RNA

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17
Q

T/F?Influenza B can infect other species but only A is humans

A

False. B infects humans only, A infects other species

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18
Q

Influenza C is a major problem these days?

A

Naw. minor pathogen bro.

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19
Q

HA and NA for Influenza stands for?

A

haemagglutinin

Neuraminidase

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20
Q

What does NS1 the non-structural protein in Influenza do?

A

anti-interferon activity

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21
Q

how man gene segments in Influenza? encodes how many proteins?

A

8 segments encode 10+ proteins

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22
Q

how many polymerase subunits does Influenza come packaged with per RNP?

A

3

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23
Q

What is RNP in Influenza?

A

Ribonucleoproteins

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24
Q

HA is the snipper in Influenza?

A

Nope, the gripper

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25
Q

NA is the gripper or snipper in Influenza?

A

snipper

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26
Q

How many subtypes of HA and NA do we know of for Influenza?

A

17 HA

9NA

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27
Q

how many subtypes of HA and NA are there for Influenza B?

A

Only ONE.

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28
Q

What are the ancestral hosts of Influenza A?

A

aquatic birds

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29
Q

Current Influenza A subtypes in humans are?

A

H1N1

H3N2

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30
Q

How is Influenza taken into the cell?

A

receptor mediated endocytosis

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31
Q

How does the 8 viral RNPs escape the vacuole once in the cell?

A

increase acid, HA changes conformation and fusion of viral envelope+endosomal membrane occurs

32
Q

Glycosylation is what?

A

ER and golgi proteins of Influenza that make up the envelope get set up near underside of cell membrane.

33
Q

How are HA and NA attached to new Influenza viruses?

A

expressed on cell surface after glycosylation prior to budding.

34
Q

Where does Influenza NA come into play?

A

cleave the sialic acid receptors from cell surface to new viruses won’t rebind to dying cell

35
Q

What does newly formed Influenza budded viruses need besides NA cleavage?

A

tryptase Clara

36
Q

What does tryptase Clara do to new Influenza viruses?

A

cleaves HA to allow it to undergo conformational change in order to all fusion and endosome escape

37
Q

Why is Influenza confined to the respiratory tract?

A

needs clara cells

38
Q

Is CD8+ Tcell immunity to Influenza long lived?

A

Nope, can be boosted by repeated exposure

39
Q

are CD8 cells cross reactive between Type A and B subtypes?

A

Nope. only between type A subtypes

40
Q

Body develops Abs to Influenza?

A

Yes, HA and NA

41
Q

What is antigenic drift in Influenza?

A

different strains WITHIN a subtype

42
Q

How does antigenic drift in Influenza occur?

A

errors of replication

43
Q

Where would antigenic drift in Influenza be advantageous?

A

If it occurs in HA or NA so the human antibodies can no longer recognize them

44
Q

Abs bind to epitopes within how many HA sites?

A

5 sites

45
Q

What happens once all 5 sites of the Influenza antigenic sites have mutated?

A

almost no one in the world have pre-existing antibodies against it and you get an epidemic.

46
Q

T/F? new Influenza strains replace older strains?

A

True. Except maybe when H1N1 escaped from a vault in Russia…..

47
Q

2 vaccines to target HA and NA to do what in Influenza?

A

HA to block attachment

NA to block release

48
Q

Influenza vaccine has 3 types, they are?

A

Influenza B

Influenza A H1N1 H3N2

49
Q

After Influenza vaccine grown in eggs, what is done to them?

A

chemically inactivated/detergent disrupted (cut up)

50
Q

T/F? Influenza vaccine induces cytotoxic T-cell response?

A

Nope. Only antibodies

51
Q

How long to prepare a Influenza vaccine?

A

6 months

52
Q

Influenza antiviral ion channel blocker does what?

A

inhibit function of M2 ion channel, prevent endosome escape of RNPs

53
Q

What does M2 on the Influenza virus do?

A

decreases pH within endosome so envelope can fuse with it and release genome into cell

54
Q

What does amantadine and rimantadine do in Influenza?

A

blocks M2 ion, prevent release of genome of Influenza virus

55
Q

does amantadine and rimantadine work on H5N1?

A

Nope.

56
Q

does amantadine and rimantadine doesn’t work on? H__N__?

A

H5N1

57
Q

Does does amantadine and rimantadine work on influenza type B?

A

Nope

58
Q

Why don’t you use does amantadine and rimantadine for everyone?

A

resistance arrises fast

59
Q

Who do you give does amantadine and rimantadine?

A

children and elderly

60
Q

What does Relenza and Tamiflu do?

A

block NA

61
Q

Does Relenza and Tamiflu work against Type A +B?

A

Yes both

62
Q

does Relenza and Tamiflu prevent disease?

A

Nope. reduces duration.

63
Q

When do you have to give Relenza and Tamiflu? how often?

A

within 2 days of symptoms, bid

64
Q

Relenza administered?

A

inhalation

65
Q

Tamiflu admin?

A

orally as prodrug

66
Q

What is antigenic shift?

A

Sudden appearance of new Influenza A virus of a new HA or NA

67
Q

How does new HA get to humans usually?

A

Zoonosis from birds

68
Q

Pandemics are rare because of Sialic acid… explain:

A

virus sees SA a2-6, avian virus sees SA2-3, but you only need single amino acid change to change that.

69
Q

What is reassortment in influenza?

A

swapping of genes upon confection of a single cell.

70
Q

example of reassortment in influenza?

A

Bird plus human viruses both infect pig, remixes and get a virus that had bird genes but can infect humans…. holy shit.

71
Q

Deaths in 1918-1919 flu pandemic killed which age group the most?

A

15-35 age group

72
Q

Is H1N1 lethal?

A

Not highly but has greater ability to replicate in lungs

73
Q

H1N1 kills old, young?

A

young adults!

74
Q

3 populations particularily vulnerable to influenza?

A

prey women
obese
indigenous

75
Q

Did closing schools help to stop influenza spread?

A

nope.

76
Q

What is so scary about H5N1 besides being fast spreading and poultry killer? so what?

A

it doesn’t need Clara cells…. it can infect ALL CELLS including the brain… holy shit.

77
Q

Is H5N1 in humans?

A

Only from humans with direct contact with birds. but about 440 cases, 60% death rate