Microbiology 14: Pandemic Flu Flashcards
Which 2 factors could allow bird flu to cross into humans?
- Mutation in polymerase protein PB2 627k
- Reassortment (when a cell is infected with human influenza and bird influenza they shuffle their RNA)
Name 3 antiviral therapies that could be used to treat flu ?
- Amantadine: targets M2 ion channel
- Neuraminidase inhibitors- oseltamivir (tamiflu), Relenza (zanamivir)
- Polymerase inhibitors- favipiravir
Which group is INACTIVATE flu vaccine given to?
Which group is live attenuated vaccine given to?
HIGH RISK GROUPS e.g. > 65 years
school-aged child
What is contained in the seasonal flu vaccine in the UK ?
Purified fraction containing HA (haemagglutinin) and NA of an inactivated virus
Why does influenza only cause respiratory pathology ?
The virus requires activation by host cell proteases that are only expressed in the respiratory tract.
Outline the 7 steps in the influenza replication cycle ?
1- The virus binds to sialic acid receptors on the host cell surface
2- The virus enters the cell via thew endosome
3- The Ph (acidic) of the endosome triggers a fusion event causing the viral genome to be released.
4- The genome travels to the nucleus and takes over host factors to drive its transcription and replication.
5- new viral products are produced.
6- The viral products assemble into a new virus at the cell surface
7- The virus buds of and is released from the host cell.
Which protein of the Influenza virus needs to be cleaved ?Which enzyme cleaves the protein ?
HA (haemaglutinin)
Tryptases in the lungs
How can an avian influenza that crosses into humans cause death ?
First there is a massive cytokine storm.
This can cause ARDS.
Which people should get the seasonal flu vaccine ?
Adults >65
Asthmatics
Diabetics
Healthcare workers
What type of vaccine is given to children ?
Intra nasal Live attenuated virus
Which enzyme in the lungs cleaves HA giving influenza a tropism for the lungs ?
Human airway tryptase (HAT)
list flu pandemics in the 20th/21st century (4)
- spanish flu (H1N1 virus)
- asian flu (H2N2 virus)
- hong kong flu (H3N2 virus)
- swine flu
what is the natural reservoir for influenza A viruses
Wild birds (ducks, geese,)
3 ingredients for pandemic infectoin
- novel antigenicity
- replicate efficiently
- transmit efficiently
Protein that allows the influenza virus to interact with host
ANP32A - gets modified after PB2 E627K mutation
