Respiratory Pathogens - RSV Flashcards
what is the leading cause of LRTIs in infants?
RSV
what is the incubation period for RSV?
4-5 days
when was RSV first identified?
4-5 days
what 2 disorders is RSV associated with?
- asthma
- bronchiolitis
what are the 2 variants of RSV?
RSV-A and RSV-B
what are 3 features of the RSV virion?
- enveloped
- 120-200nm in diameter
can be either:
- spherical
- filamentous
- asymmetric
what are 3 features of the genome of RSV?
- negative sense
- linear
- 15.2 kilobases long
what does the matrix protein form in RSV?
the capsid
what is the attachment protein in RSV called?
G glycoprotein
what is the fusion protein called in RSV
F glycoprotein
what are 2 features of the RSV G-glycoprotein attachment protein
- highly glycosylated
- highly variable
what are the 2 forms of the G-glycoprotein attachment protein in RSV?
- membrane anchored (Gm)
- secreted (Gs)
what does the membrane-anchored Gm attachment protein in RSV do?
allows for viral attachment to heparin sulphate receptors of epithelial and type I alveolar cells
what does the secreted Gs attachment protein on RSV do?
limits host neutralisation
what are 2 features of the F fusion protein in RSV?
- highly conserved (maintained)
- potential vaccine target
outline the 5 steps lifecycle of RSV
- attachment to epithelial or type I alveolar cells via G-glycoproteins attaching to heparin sulphate recptors OR cell-surface fusion using F proteins
- RSV is taken into the cell via endocytosis
- fusion to the host cell within an endosome occurs
- genetic material of RSV is released and then transcripted to copy material, and also translated to produce proteins
- reassembly of a new virion which leaves the surface of the host cell to infect other cells
outline the 6 steps of the pathogenesis of RSV
- there is increased viral load
- blockage of the cell cycle process to maximise viral replication
- this **disrupts **ciliated epithelial cells
- this causes inflammation AND mucosal oedema
- this promotes monocyte lung infiltration
- this results in syncytia formation
what does syncytia formation in RSV lead to?
- bursting of syncytia which can lead to mucus obstruction in the airways
what is are symptoms of RSV and which is the big symptom?
- restriction
- obstruction
- runny nose
- shortness of breath
- hypoxia
- pneumonia and bronchiolitis
BIG symptom:
- wheezing
how much is the correlation percentage between children who have RSV infection and their development of asthma in life?
40%
what are 3 factors that can increase mortality rate of RSV
- congenital heart disease
- congenital lung disease
- immunodeficiency
what are 4 HOST risk factors of RSV
- age (young and old)
- being male
- vitamin D deficiency
- genetic polymorphisms in innate and adaptive immune response genes, surfactant protein genes and host receptor genes
what are 3 environmental risk factors for RSC
- exposure to cigarette smoke due to impact on epithelial cells which induces necrosis
- air pollution
- the time of year
how can we prevent and treat RSV
- infection monitoring
- vaccination
what are 4 medical treatments to treat RSV
- hydration and antipyretics
- oxygen therapy
- RSV neutralising antibodies
- Intensive care support
