Micro - influenza

Question 1

natural reservoir of Influenza A virus

Answer 1

ducks

Question 2

Why does influenza virus only cause respiratory disease?

Answer 2

influenza requires cleavage of HA by host cell proteases - these are only present in resp tract cells

Question 3

How does influenza virus enter cells

Answer 3

Binds to HA

Question 4

What needs to happen to influenza virus to affect human cells?

Answer 4

cleavage of haemagluttinin by host cell proteases

Question 5

what ws the one ‘good’ thing about the H7N9 avian influenza? i.e. why did it not result in a pandemic

Answer 5

No person-to-person transmission

Question 6

3 “ingredients” which constitute a pandemic virus

Answer 6

1. Person to person transmission
2. Novel antigenicity
3. Efficient replication in human airway

Question 7

what aspect of influenza viruses is important in determining if it will replicate in human cells?

Answer 7

PB2 protein must have lysine (if it has glutamate, then it won’t replicate in humans)

Question 8

how does an influenza virus compete with human mucus barrier to infect the respiratory tract?

Answer 8

Neuraminidase cuts through sialic acid in mucus

Question 9

Which age ranges did H1N1 tend to affect and why?

Answer 9

Younger people more often affected as older patients had seen similar virus before

Question 10

specific genetic predisposition to severe H1N1 infection?

Answer 10

IFITM3 mutation

Question 11

Amantadine - MOA?

Why is it useless?

Answer 11

Targets the M2 ion channel

• single point mutation in M2 renders the virus resistant

Question 12

Name 2 neuraminidase inhibitors?

Answer 12

Oseltamivir

Zanamivir

Question 13

Describe the composition of the influenza vaccine given to high risk groups in the UK?

Answer 13

Purified fractions of HA and NA from inactivated viruses

Question 14

Diff btw influenza vaccine given to children vs elderly

Answer 14

Elderly:inactivated vaccine
Children: live attenuated vaccine