Flu

Question 1

How is flu transmitted?

Answer 1

Droplet inhalation
Direct contact
Exhaled breath

Question 2

What are the primary sites of infection?

Answer 2

Epithelial cells lining the respiratory tract

Question 3

What type of virus is the flu virus?

Answer 3

Pleomorphic (80-120nm in diameter)

Question 4

What are the three proteins associated with the outer membrane?

Answer 4

HA
NA
M2

Question 5

What is beneath the membrane?

Answer 5

Sheath of matrix protein

Question 6

How many RNA segments are there?

Answer 6

8

Question 7

What mediates virus attachment?

Answer 7

HA (hemagglutinin protein) - recognises sialic acid on the surface of epithelial cells

Question 8

How does the virus enter the cell?

Answer 8

Endosomes - fusion is mediated by HA protein, changes conformation due to low pH
RNP release is mediated by M2 protein (x4) produces a pore
Causes influx of hydrogen ions into the cell and allows breakdown of the matrix protein layer and the segments are released into the cell

Question 9

What does the NA protein do?

Answer 9

Cleaves sialic acid from the previously infected cell to prevent re-entry

Question 10

Through what methods does the virus rapidly mutate?

Answer 10

Antigenic shift: two different viruses mix (re-assortment)

Antigenic drift: influenza virus makes an error when replicating

Question 11

What treats the flu?

Answer 11

Adamantanes (amantadine and rimantadine)
Low levels it is specific for influenza A
Rimantadine has an extra methyl group
Amantadine prevents formation of the M2 ion channel

Question 12

What are neuraminidase inhibitors?

Answer 12

Tamiflu (C4 OH & glutamic acid 119) and relenza (addition of a positive charged guanidino group) - structural based drug design

Question 13

What are the three types of flu and which one infects humans?

Answer 13

Flu A, flu B and flu C
Humans infected by flu A and B
The reservoir of Flu A is the duck