Influenza infections Flashcards
Is influenza dsDNA or ssRNA?
ssRNA
What does influenza recognise?
Sialic acid receptors
What is our initial response to influenza?
NFkB–>TNFa, IFNb and IL-8.
Attraction of NK, B and T cells.
More cytokines
What is the first encounter with a foreign antigen called?
Primary immune response
What is the second encounter with a foreign antigen called?
Secondary immune response
Primary response produces more IgM or IgG?
IgM
Secondary response produces more IgM or IgG?
IgG
How many HA subtypes are found in influenza type A viruses in humans?
3- H1 H2 H3
How many NA subtypes are found in influenza A in humans?
2- N1 N2
What is antigenic drift?
Gradual accummulation of mutations that allow the hemaglutinnin to escape neutralising antibodies
How many changes in antigenic sites are epidemic strains thought to have?
3 or more
Does antigenic drift cause pandemics or epidemics?
Epidemics
What is the most common form of influenza?
Seasonal influenza
What is the new strain of seasonal influenza usually derived from?
Previous strains
Antigenic shift causes epidemics or pandemics?
Pandemics
When does pandemic influenza occur?
When a new strain of virus is formed
Which type of mutation do humans have no natural protection to? Antigenic drift or shift?
Antigenic shift
Which strains can you not predict? antigenic shift or drift?
Antigenic shift
What is a vaccine?
Often a safe (inactivated) dose of the pathogen
How many types of influenza viruses are there?
4- A B C D
Which types of influenza strain cause seasonal epidemics?
A and B
What does influenza C usually cause?
Mild respiratory illness- not epidemics
Which type of influenza affect cattle?
D
What should influenza vaccine contain?
2 X A
1 X B
What do you treat the vaccine with to get inactivated form?
Formaldehye
What do you treat the vaccine with to get split vaccine?
Ethyl ether
What do you treat the vaccine with to get subunit vaccine?
Detergents
What is FluMist?
Nasal spray flu vaccine- cold adapted influenza viruses propagated by infection of cells in culture and manufactured in eggs
What are 4 critical factors in influenza vaccine manufacturing?
Growth potential of seeds
Timing of strain selection
Potency test reagents
What are amantadine and rimantadine?
M2 inhibitors
What are oseltamivir and zanamivir?
Neuraminidase inhibitors
How does amantadine work?
Intereferes with function of transmembrane domain of M2 protein.
Interferes with virus assembly during replication.
Decrease the release of influenza particles into host cell
What are the problems with amantadine?
Rapid development of resistance.
Wide range of side effects and toxicity
Which is less toxic, amantadine or rimantadine?
Rimantadine
Are amantadine and rimantadine NICE recommended?
No
What are the advantages to Neuraminidase inhibitors?
Active against all strains of influenza (ABC) and all serotypes
What are zanamivir and oseltamivir?
Neuraminidase inhibitors
What is zanamavir approved for?
Treatment of influenza A and B
What is oseltamivir approved for?
Treatment of influenza A and B
What are the adverse effects of Oseltamivir?
Mild to mod nausea/vom
