Respiratory Viruses Flashcards
what are the 3 types of influenza viruses?
A
B
C
Which type of influenza virus is most common and associated with greatest concerns?
A
only influenza virus type that has an animal reservoir
A
virus family of influenza
orthomyxoviridae
virus family of adenovirus
adenoviridae
virus family of rhinovirus
picornavirus
influenza virion type
enveloped
adenovirus virion type
non-enveloped
rhinovirus virion type
non-enveloped
influenza genome classification
8 segmented (-)ssRNA
influenza is identified by:
surface antigens HA and NA
what influenza surface antigen is critical to budding?
NA
influenza mode of transmission
aerosol, large and small droplets
influenza vaccine type
live attenuated
how are influenza pandemics thought to arise?
from avian strains
how are adenoviruses characterized?
by their serotype
adenovirus genome
dsDNA
adenovirus entry
via coxsackie-adenovirus receptor (CAR)
how does adenovirus leave its capsid?
pH triggered capsid disassembly
what are the 3 phases of adenovirus gene expression
immediate-early
early
late
influenza transcription and replication take place where?
nucleus
influenza control/treatment
antiviral tx (amantidine)
zanamivir (tamiflu)
supportive care
how does tamiflu work against influenza virus?
blocks release of budding virions
resistance uncommon
how does antiviral treatment work against influenza virus? (amantidine)
blocks entry, inhibits M2 (influenza ion channel) activity
resistance common
avian influenza
H5N1
H5 or H7 strains
highly pathogenic
why does avian influenza replicate so much in body?
HPAI strains leave residues at HA cleavage site which allows replication throughout body
H5N1 is characterized by:
skin lesions, necrotic & swollen combs, systemic infection
immediate-early phase of gene expression in adenovirus
E1A portion of genome
early phase of gene expression in adenovirus
5 genome sections
DNA replication & post-transcriptional events
late phase of gene expression in adenovirus
take over of cellular mRNA synthesis
adenovirus genome replication
replicated 5’ to 3’
one strand displaced
adenovirus genome replication primed by
protein pTP
adenovirus E3 gene produces proteins important to
host immune evasion
adenovirus blocks
MHC-I expression to reduce CTL killing
TNF induced apoptosis
IFNa,b action keeping protein translation alive
during what part of cell cycle does adenovirus DNA replication occur?
S phase
T/F? majority of adenovirus respiratory disease occurs in people >14
false; under 14
ARD is caused by adenovirus serotypes
4, 7
adenovirus vaccine?
available to military personnel 17-50
adenovirus respiratory disease symptoms
like common cold
inflammation, cough, nasal congestion
rhinovirus is frequent cause of:
mild URT infections
T/F? Rhinovirus has small antigenic diversity
false; over 100 serotypes making it difficul to develop vaccine
rhinovirus vaccine?
no. too many serotypes
no antivirals either
T/F? Rhinovirus has animal reservoir
false; human only
rhinovirus symptoms
red nose, vessel dilation
mucopurulent runny nose
epithelial damage
