Influenza Virus

Question 1

Influenza virus virology

Answer 1

Enveloped virus
Wild type virion
Filamentous morphology
Negative sense segmented RNA genome

Question 2

Influenza natural reservoir

Answer 2

Ducks

Question 3

How does influenza A replicate in humans

Answer 3

1. Virus activated by human airway tryptase and the temperature of 36 degrees favours its replications
2. In the lung, influenza uses haemaglutinin binds to sialic acid on the cell membranes, allowing entry into the cell
3. Neuraminidase cleaves sialic acid to exit the cell

Question 4

Factors for a successful pandemic

Answer 4

1. Novel antigenicity
2. Efficient replication within the airway
3. Efficient transmission between people

Question 5

Define antigenic drift

Answer 5

point mutations → gradual changes of an antigen over time

Question 6

Define antigenic shift

Answer 6

co-infection → recombination of genomic segments → rapid change of possibly a whole antigen

Question 7

What antivirals are available for influenza

Answer 7

Amantadine - targets M2 ion channel
Baloxovir - polymerqase inhibitor
Neuraminidase inhibitor - oral osaltamivir, inhaled zanamivir