Case Study Comparison Chart: Influenza

Question 1

describe the structure of the influenza virus

Answer 1

• lipid envelope
• NA
• HA
• SS(-)RNA
• replicase
• M2 ion channel

Question 2

what is the role of HA?

Answer 2

aids in attachment to sialic acid on ciliated epithelial cells

Question 3

what is the role of NA?

Answer 3

aids in release

Question 4

what is responsible for antigenic drift?

Answer 4

mutations

Question 5

what is responsible for antigenic shift?

Answer 5

recombination of viral genome

Question 6

which is the only class of influenza virus to experience antigenic shift?

Answer 6

A

Question 7

what is the responsibility of the M2 ion channel in an influenza infection?

Answer 7

M2 ion channel mediates release of viral genome nucleic acid into cytoplasm

Question 8

why is it significant that influenza is an RNA virus?

Answer 8

high mutation rate

Question 9

describe the genome of an influenza virus. why is that significant?

Answer 9

segmented. errors can occur during recombination of viral genome, causing antigenic shift

Question 10

what are the types of influenza virus that matter?

Answer 10

A, B, C

Question 11

which influenza types cause an illness in humans?

Answer 11

A, B, C

Question 12

which influenza types are responsible for seasonal epidemics?

Answer 12

A and B

Question 13

which influenza types cause minor illnesses?

Answer 13

C

Question 14

how are influenza A types named?

Answer 14

after the H and N types that are involved ex. H1N1

Question 15

how are influenza B types named?

Answer 15

based on where they were isolated ex. B/Victoria

Question 16

wide host range for different strains?

Answer 16

A

Question 17

influenza A host range: wide or narrow?

Answer 17

wide

Question 18

examples of influenza type A hosts?

Answer 18

birds, pigs, humans

Question 19

which influenza type is responsible for pandemics?

Answer 19

A

Question 20

influenza type A is responsible for

Answer 20

pandemics

Question 21

influenza type B is responsible for

Answer 21

NOT pandemics

Question 22

influenza B host range: wide or narrow?

Answer 22

narrow

Question 23

higher mutation rate: influenza type A or influenza type B?

Answer 23

A

Question 24

lower mutation rate: influenza type A or influenza type B?

Answer 24

B

Question 25

what is the incubation period for influenza?

Answer 25

roughly two days

Question 26

describe some symptoms of influenza:

Answer 26

headache, fever, sore throat, dry/tight cough, chest pain, muscle aches, weakness, extreme fatigue

Question 27

how is influenza spread?

Answer 27

via droplets or fomites

Question 28

what is the most telling symptom of flu?

Answer 28

extreme fatigue

Question 29

what are some symptoms of flu?

Answer 29

headache, fever, sore throat, dry/tight cough, chest pain, muscle aches, weakness

Question 30

flu can sometimes lead to... (2)

Answer 30

Reye's syndrome or Guillain-Barre syndrome

Question 31

what treatment exists for influenza? how do they help? (4)

Answer 31

influenza-specific medicine: - interfere with uncoating process, act on M2 - NA inhibitors - replicase inhibitors - antibiotics for secondary infections (like bacterial pneumonia)

Question 32

who is most at risk for secondary infections because of the flu?

Answer 32

- 65+ or younger than 5 - immunocompromised - pregnant

Question 33

why is there no immunity to a flu pandemic when it occurs? (3) how often does it occur?

Answer 33

in a storm, the escalator drifts. - antigenic drift - mucociliary escalator is destroyed - cytokine storm occurs periodically.

Question 34

how is the mucociliary escalator destroyed as a result of the flu?

Answer 34

infected epithelial cells die and slough off, destroying the mucociliary escalator

Question 35

when does a cytokine response occur?

Answer 35

extreme immune response

Question 36

antigenic drift vs. shift:

Answer 36

DRIFT: - slow, constant changes aka mutations during viral replication - seasonal flu SHIFT: - change in H&N type - pandemics

Question 37

what prevention methods are available against influenza?

Answer 37

VACCINES!

Question 38

what can you tell me about flu vaccines? for instance, how many types are there, what are they, and what are their characteristics?

Answer 38

inactivated - grown in chicken eggs/cell cultures - quadrivalent live attenuated - nasal flu mist - only for ages 2-49 - cannot be given to immunocompromised - effectiveness varies

Question 39

what can you tell me about influenza vaccine production?

Answer 39

- new vaccine each year - start production in Jan to distribute in the fall - try to predict strains that are circulating and that previous vaccines don't protect against

Question 40

what are the steps of an influenza infection?

Answer 40

1. get infected (fomite or droplets) 2. attachment of virus 3. enter cell via receptor-mediated endocytosis 4. M2-mediated release of viral nucleic acid into cytoplasm 5. host cell protein and DNA synthesis stopped 6. viral RNA and protein synthesis 7. HA and NA embedded in host cell membrane 8. mature virions bud from host cell via NA

Question 41

how does an influenza virion exit the cell?

Answer 41

budding

Question 42

how does an influenza virion enter the cell?

Answer 42

receptor-mediated endocytosis