Microbio Week 11 - Influenza (Exam 3)

Question 1

How many types of influenza are there?

Answer 1

3

Question 2

What does influenza A infect?

Answer 2

Humans
Swine
Avians

Question 3

What is influenza A capable of?

Answer 3

Antigenic drift AND shift

Question 4

What does human influenza combine?

Answer 4

Hemagglutinin (HA) 1, 2, or 3 with neuraminidase (NA) 1 or 2

Question 5

Which influenza is the cause of most epidemics and all pandemics?

Answer 5

Influenza A

Question 6

What does influenza B infect?

Answer 6

Humans

Question 7

What is influenza B capable of?

Answer 7

Antigenic drift

Question 8

What can result in reinfection and changing the vaccine in influenza B? (ON EXAM)

Answer 8

Antigenic drift

Question 9

What influenza has rare epidemics but no pandemics?

Answer 9

Influenza B

Question 10

Results in small changes in the virus

Answer 10

Antigenic drift

Question 11

Large changes; the swapping of viral RNA segments between human and avian, human and swine, or all three viruses

Answer 11

Antigenic shift

Question 12

Where are the most critical mutations as a result of antigenic drift?

Answer 12

Hemagglutinin envelope protein

Question 13

What do mutations in hemagglutinin have the potential to allow?

Answer 13

Allows the virus to escape neutralizing ABs

Question 14

What will enable the virus to reinfect people and is a reason the change the flu vaccine?

Answer 14

Antigenic drift in hemagglutinin

Question 15

_______ are the perfect mixing place for antigenic shift, as both human and avian influenza can infect them.

This mixing can sometimes lead to a vastly new virus that can cause a ___________

Answer 15

Pigs; pandemic

Question 16

How is influenza spread?

Answer 16

Respiratory droplets
Fomites

Question 17

What type of virus is influenza - naked or enveloped?

Answer 17

Enveloped

Question 18

T/F: Since influenza is enveloped, it can be killed with detergents, heat, acid, and drying

Answer 18

True

Question 19

What is the typical number of deaths in the flu season? What population has the most deaths?

Answer 19

<1/1000

Most deaths are people > 65 years old

Question 20

T/F: Most hospitalizations occur in people with underlying health conditions, but previously healthy adults and children are hospitalized, and some die yearly

Answer 20

True

Question 21

A pandemic strain of influenza will become the new sessional influenza until supplanted by what?

Answer 21

A new pandemic strain

Question 22

Are influenza infections local or generalized? How long is the incubation time for influenza infections?

Answer 22

Local infection; short incubation time

Question 23

How long do symptoms of influenza last?

Answer 23

2-3 days, can be up to 5

Question 24

When do adults shed the influenza virus?

Answer 24

1 day before symptoms to 5-7 days after

Question 25

Children can shed the influenza virus up to ____ days after symptoms

Answer 25

10

Question 26

1/3 of all influenza deaths are due to what?

Answer 26

Secondary bacterial pneumonia

Question 27

T/F: Pneumonia caused by influenza (primary viral pneumonia) is rarer than bacterial pneumonia, but is generally worse and has a high fatality rate

Answer 27

True

Question 28

What does hemagglutinin bind to?

Answer 28

Sialic acid

Question 29

Which sialic acid linkage does the human influenza virus bind to?

Answer 29

a2-6 linkage

Question 30

Where is the a2-6 linkage found in the body?

Answer 30

Upper respiratory tract (HIGH levels) Lower respiratory tract (LOW levels)

Question 31

Bacterial pneumonia is most prevalent in people with underlying _______ problems, but even the healthy can get secondary bacterial infections

Answer 31

lung

Question 32

How does secondary bacterial pneumonia occur in influenza infections? (4)

Answer 32

1. Killing airway epithelial cells makes it easier for bacteria to bind in the airway 2. Influenza kills alveolar macrophages that help prevent bacterial infection 3. Airway edema and dead cells create a nutrient-rich environment for bacterial growth 4. Viral neuraminidase inactivates some innate antimicrobials that might help kill bacteria and expose bacterial attachment sites

Question 33

Which vaccine? A detergent disrupted inactivated virus. Just the HA and NA are isolated and put in the vaccine

Answer 33

Inactivated influenza vaccine (IIV)

Question 34

Which vaccine? Contains a cold-adapted influenza virus containing the HA and NA in the inactivated vaccine

Answer 34

Live attenuated influenza vaccine (LAIV)

Question 35

Which vaccine? Contains an entirely recombinant HA protein grown in cell culture

Answer 35

Subunit vaccine (RIV)

Question 36

All influenza vaccines will be _________

Answer 36

trivalent

Question 37

What does the trivalent vaccine contain?

Answer 37

2 strains of influenza A 1 strain of influenza B

Question 38

Protection from infection is achieved how long after vaccination?

Answer 38

2 weeks

Question 39

Zanamivir and Oseltamivir (Tamiflu) are _____________ inhibitors

Answer 39

neuraminidase

Question 40

What do Zanamivir and Oseltamivir (Tamiflu) prevent?

Answer 40

Prevent the budding and release of the virus

Question 41

Zanamivir, Oseltamivir (Tamiflu), and Baloxzvir (Xofluza) must be used within ____ to _____ days of infection to have max. effect

Answer 41

2 to 3

Question 42

Baloxzvir (Xofluza) is a cap-dependent ______________ inhibitor

Answer 42

endonuclease

Question 43

What does Baloxzvir (Xofluza) block?

Answer 43

Blocks the virus from "snatching caps" and transcribing viral mRNA

Question 44

T/F: Baloxzvir (Xofluza) is as effective as neuraminidase inhibitors

Answer 44

True

Question 45

How many people were infected during the 1918 flu epidemic?

Answer 45

1/3 to 1/2 world population

Question 46

What was the fatality rate during the 1918 flu epidemic?

Answer 46

>2.5%

Question 47

The 1918 flu epidemic had a W-shaped mortality curve, meaning what?

Answer 47

There were more deaths in the 18-40 year age than normal for influenza

Question 48

What 3 things make a highly virulent strain of influenza?

Answer 48

1. Receptor usage 2. Viral virulence factor present in avian flu and 1918 flu, but not in human influenzas 3. Little immunity to the new virus

Question 49

What sialic acid linkage do avian strains recognize?

Answer 49

a2-3

Question 50

Where is the a2-3 sialic acid linkage (avian strain) found in the body?

Answer 50

Upper respiratory tract (LOW levels) Lower respiratory tract (HIGH levels)

Question 51

What does the avian strain cause?

Answer 51

More severe LRT infection Less spread from person to person

Question 52

What does the human strain cause (a2-6 linkage)?

Answer 52

Less chance of LRT infection More efficient spread from person to person

Question 53

If you have a strain like 1918 that can efficiently infect both the upper and lower respiratory tract, what can happen?

Answer 53

More severe LRT infection More efficient spread from person to person

Question 54

What are we worried about with antigenic shift?

Answer 54

Pandemic

Question 55

How many main avian influenzas have crossed over to infect humans in substantial numbers?

Answer 55

2

Question 56

Are the 2 avian influenzas that have crossed over to infect humans efficiently spread from person to person?

Answer 56

NO

Question 57

Do the 2 avian influenzas that have crossed over to infect humans have a high fatality rate?

Answer 57

Yes

Question 58

Many places worldwide, including the US, are having problems with a slightly different clade (2.3.4.4b) of ______ that is highly pathogenic in poultry

Answer 58

H5N1

Question 59

What does H5N1 infect?

Answer 59

Wide variety of land and sea mammals

Question 60

What is infecting US dairy cattle?

Answer 60

H5N1

Question 61

There are designated HPAI or LPAI-High Pathogenic or Low Pathogenic Avian Influenzas. What is this based on?

Answer 61

Ability of the virus to kill chickens (NOT humans)

Question 62

Viral protein that cleaves sialic acid

Answer 62

Neuraminidase

Question 63

Receptor binding viral protein

Answer 63

Hemagglutinin