11.5 Respiratory Viruses Flashcards
What are the components of teh influenza virion wall?
Haemagglutinin and Neuraminidase
What is the role of Haemagglutinin (HA)
attaches to the proteins on the cell surface and allows the virus to get in - binds to caulic acid on the cell surface
What is the role of Neuraminidase (NA)
Cleaves and allows the virus to get away from the cell (enzyme)
How is influenza A classified?
based on the HA and NA
How does immunity to influenza work?
it is the antibodies that recognise HA and NA that prevent reinfection with the same strain
The anti-HA is the neutralising antibody and the anti-NA is protective not neutralising
Why does antigenic and genetic drift occur?
Many people have protective antibodies against HA and NA so there is strong selective pressure to change these proteins and evade antibody recognition
Who is respiratory syncytial virus most common in?
Coincides with winter and 90% of hospitalisations are in children under 1
What are the two main branches of paramyxoviridae
Paramyxovirinae: measles, mumps, hendra, canine distemper, newcastle disease virus
Pneumovirinae: RSV, human metapneumovirus
What family of viruses does RSV belong to?
paramyxoviridae
What is the major risk factor for RSV?
Anything that compromises breathing, cardiac or immune function
What are the types of rhinovirus?
Polio
Coxsackievirus
Foot and mouth disease
Who most commonly gets rhinovirus and how is it usually spread?
Children are more commonly affected and it is mainly spread within the family unit
Why is rhino virus so tough?
It is non encapsulated
give an example of genetic mutation by influenza
If two strains co infect a single cell then the genomes can re assort and create new strains
define pandemic
sustained community spread in more than one global region
