influenza pathology Flashcards
Why is the influenza virus a major public health concern
It has the potential to cause pandemics and evolve rapidly
Give an example of an influenza strain with global spread
H5N1
what family does the influenza virus belong to
Orthomyxoviridae
Which influenza type is responsible for pandemics
Influenza a
which influenza type does not cause pandemics but infects human
Influenza b
How many segments does rhe influenza d virus
seven
What is the outer structure of the influenza virus derived from
the host cell membrane
Name the 3 key envelope proteinns of innfluenza
Hemagglutin(HA) ,Neuraminidase (NA) and M2 proteiin
What is the function of Ha
binds to host cell receptors and mediates membrane fusion
What is the function of NA
Cleaves sialic acid to facilitate virus release
How are influenza virus subtypes named
Based on their HA and NA proteins
What receptor linkage does human adapted influenza bind to
a2-6 sialic acid linkages
What receptor linkage does influenza prefer
a2-3 sialic acid linkages
How is influenced transmitted
Through respiratory droplets and direct contact
What determines the severity of influenza infection
the strains pathogenicitiy and host immune response
what 2 mechanisms drive influenza virus evolution
Antigenic drift and antigenic shift
How can zoonotic transmissionn lead to pandemics
By allowing the virus to jump from animals to humans and new mutations
How has H5N1 spread globally
Through bird migration
Why is H5N1 in mammals a concern
it increases the risk of human to human transmission
What is the primary prevention method for influenza
Vaccination
name an antiviral drug that targets neuraminidase
oseltamivir (Tamiflu)
How does influenza bind to host cells
HA binds to sialic acid recptors on epithelial cells
What process follows receptor binding
Endocytosis
What triggers membrane fusionn inside the host cells
a pH drop in the endosome
What viral structure mediates fusion
The HA fusion peptide
Which allows viral RNA to be released into the cytoplasm
matrix (m ) protein breakdown and M2 ion channel activity
What role does M2 protein play in uncoating
It allows H+ innflux to dissociate RNPs
How do RNPS enter the nucleus
Via importins
What enzyme initiates viral RNA synthesis
RNA dependent RNA polymerase (RdRp)
What are the 2 types of RNA synthesis in influenza
Transcription(mRNA production for viral proteins)
Replication (copying of(-) sense genome for virions
What protein facilitates RNP export
NS2(NEP)
What pathway does RNP export follow
The CRM1 pathway
Where are HA, NA and M2 proteins processed
In the golgi apparatus before trafficking to the plasma membrane
What protein helps package all 8 genome sequences
M1 Matrix protein
What enzyme prevents new virion from reattaching to the host cells
Neuraminidase (NA )
How are new virions released from the cells
By budding from the plasma membrane
What host machinery does influenza use for replications
The host cells nucleus and protein synthesis pathways
What contributes to seasonal outbreaks and pandemic
Antigennic variation (drift and shift)
Why is studying the influenza life cycle important
It helps develop effective vaccines and antiviral treatments.
