Middleton- Respiratory viruses Flashcards
Influenza virus type __ is the most common, and is associated with the greatest concern
Type A
Influenza virus: virus type, genome, virion
- Orthomyxoviridae
- (-)ssRNA
- enveloped
Influenza will produce what protein for cell attachment?
HA protein
hemagglutinin
influenza can be Identified by surface antigens ___ and ___
HA and NA
what is the major determinant between avian and human strains of influenza?
HA proteins
type __ influenza has an animal reservoir
type A
what causes membrane fusion to the influenza virus?
Conformation change triggered after cell attachment by pH change in endosome
the transcription and replication of the influenza virus takes place where?
in the nucleus
the _______ of influenza escapes nucleus and buds from cell surface
Protected genome (RNP core)
what protein is critical for the budding of the influenza virus from the host cell?
NA protein
after infection with influenza, a person is contagious for how long?
- from the day before symptom onset until 5 days later
- children are infectious longer
how is influenza transmitted?
aerosol (large & small droplets)
what type of flu can influenza cause?
Seasonal (interpandemic) flu
what complication can arise from influenza infections?
- Viral pneumonia
- Bacterial pneumonia
- Otitis media
what type of vaccine is given for influenza?
Attenuated live vaccine
what causes the need for new influenza vaccines every year?
antigenic shift
-virus mutation
how many major flu pandemic have their been?
4
- 1918 spanish flu
- 1957 asian flu
- 1968 hong kong flu
- 2009 H1N1
Influenza pandemics are thought to arise from ____ strains
avian
Adenoviruses are characterized by their _____
serotypes
Adenovirus: virus type, genome, virion
- Adenoviridae
- dsDNA
- non-enveloped
the Adenovirus enters the host through what receptor?
CAR receptor
coxsackie-adenovirus receptor (CAR)
__ triggers the capsid disassembly of Adenoviruses, which then move where?
pH triggers disassembly
moves to nucleus
Adenovirus gene expression occurs in _____ phases
three
what happens during the late gene expression phase of the Adenovirus?
virus take over of cellular mRNA synthesis
