10.28.2022. Flu: my questions Flashcards
describe the structure of influenza virus
- enveloped
- ss negative RNA
- segmented genome
where do influenza viruses get their lipid envelope?
from host cells
regarding the surface antigens, there is one thing that is essential for pathogenesis. what is it?
glycoproteins
what is essential for pathogenesis in infleunza
glycoproteins
what does H or HA antigen stand for?
hemagglutinin
what does HA do?
aids in attachment to ciliated epithelial cells
what does N or NA stand for?
neuraminidase
what does NA do?
aids in release
which H subtypes are spread in humans?
1,2,3
which N subtypes are spread among humans?
1,2
which two types of flu viruses cause seasonal epidemics in the US?
A and B
what do A and B viruses cause in the US?
seasonal epidemics
how are influenza A viruses divided into types?
based on H and N ex. H1N1
host range and mutation rate for HA?
wide host range (birds, pigs, humans)
high mutation rate
host range and mutation rate for NA?
narrow host range
lower mutation rate
how are B viruses divided into subtypes?
by the location in which they were isolated ex. B/Victoria
which flu virus is responsible for pandemics?
A
are B viruses responsible for pandemics?
no
are A viruses responsible for pandemics?
oftentimes yes
incubation period of flu?
about two days
name three symptoms of flu
headache, fever, sore throat, dry tight cough, chest pain, extreme fatigue, muscle aches, weakness, malaise.
what is the most important symptom of the flu?
extreme fatigue
who is most prone to developing a secondary infection and may need hospitalization?
ages 0-5, 65+
name two syndromes that may occasionally develop as a result of flu
Reye’s syndrome
Guillain-Barre Syndrome
Reye’s syndrome results from ____
influenza
Guillain-Barre Syndrome may develop from…
what is it?
all kinds of viral infection. immune disorder
how is influenza acquired/how does one get infected?
aerosolized respiratory secretions (droplets) or via fomite transfer
what does the influenza virus attach to? how does it attach?
respiratory epithelium cells.
HA glycoprotein on virus attaches to sialic acid on host respiratory epithelial cells.
how does influenza virus enter the cell?
endocytosis
how do mature virions exit the host cell?
budding
does H&N type change in antigenic drift or shift?
shift
antigenic drift: ______ influenza
seasonal
antigenic shift: ________ influenza
pandemic
how often do flu epidemics occur?
every year with seasonal influenza
how often do flu pandemics occur?
periodically
why do flu pandemics occur?
new strain = limited/no immunity = more cases = more deaths
what is antigenic drift?
slow, constant changes as virus replicates.
is antigenic drift fast or slow?
slow
how do changes occur in antigenic drift?
mutations during replication
what does better binding mean for flu viruses?
what do mutations have to do with binding?
increased immunity. mutations weaken the binding each time.
what is antigenic shift? what does it result in?
abrupt, major changes in a virus, resulting in changes to/new H and/or N type
is antigenic shift fast or slow?
fast
describe the host range of antigenic shift?
fast
the inactivated flu vaccine is —valent
tri or quad
what antibodies are found in the inactivated flu vaccine?
IgG only
how is the live attenuated vaccine administered?
nasal flu mist
what antibodies are present in the live attenuated vaccine?
IgA and IgG
who should the live attenuated vaccine administered to?
only for ages 2-49
who should the inactivated vaccine be administered to?
egg-free or high does for >65 years
what are the two options for the influenza vaccine?
inactivated vaccine
live attenuated vaccine (nasal flu mist)
