influenza Flashcards
signs and symptoms
- fever
- headache
- muscle aches/pains
- fatigue
- sore throat
- cough
transmitted via
- contact with respiratory droplets
- airborne via respiraotry droplet nuclei
- contact with fomites contaminated with respiratory droplets
shape
enveloped
(-) ss RNA genome
segmented genome
pathogenesis
- the virus attaches to and infects epithelial cells in the URT
- replicates inside the cells, damaging the cells
- spreads to lower respiraotry tract and sometimes secondary bacterial infections occur
virulence factor
spikes
* hemagglutinin
* neuraminidase
hemagglutinin
- fililitates viral entry
- binds to sialic acid on host cells which act as receptors
- sialic acid is a small sugar that is attached to many different proteins on the cell surface
neuraminidase
- facilitates virion release from the cell by cleaving sialic acid
- degrades mucin layer of respiraotry tract
antigenic drift
MINOR changes caused by genetic mutation
* resulitng from RNA replication errors
* RNA polymerase has low fidelity
* graudal
* occurs with influenza A, B, C
Antigenic shift
MAJOR changes caused by genetric reassortment
* adrupt
* occurs with influenza A only
Influenza A
- severe
- animal reseervoir
- shift AND drift
influenza B
- moderate
- epidemic
- drift
influenza C
- mild
- sporadic
- drift
Avian H5N1 (bird flu)
- highly virulent in humans
- cannot be transmitted human-to-human
treatment
infleunza antivirals
NA inhibitor drugs
inhibit neuraminidase from unbinding to host cell, stops viral replication
prevention
flu vaccines
flu vaccines
- contain 3 or 4 different viruses (mix of A subtypes and B strain)
- greatly reduces the incidence of flu and the severity of flu-related illness
2 types of flu vaccines
inactivated vaccine (flu shot)
live attenuated vaccine (nasal spray)
inactivated influenza vaccine
flu shot
TIIV (trivalent inactivated influenza vaccine (3 strains)
flu vaccine exceptions
egg allergies and preadverse reactions to vaccine
