L79 Flashcards
What disease does rhinovirus cause? Transmission?
The common cold is transmitted by resp droplets
What are unique replication requirements of rhinovirus?
Prefers the cold
Nose > lungs
Why does rhinovirus make asthma worse?
Turns on Th2 response
Describe the rhinovirus genome - what is unique?
IRES = internal ribosome entry site
- Ribosome knows to start here, don’t need to scan the genome for start codon
Means rhinovirus RNA genome doesn’t need to be capped like human RNA does
Rhinovirus pathogenesis - how does it change host cell processes? Where in the host cell does it replicate?
Infects nasal epithelium
Shuts off all host translation to push viral translation - preferential replication
RNA genome = replicate in cytoplasm
How does rhinovirus leave host cells
Lysis
Describe the timeframe of rhinovirus cold - what immunity is responsible for clearing the cold?
0 = infected Day 2 = viral peak in serum Day 3-4 = symptom peak Day 5 = virus gone from serum Innate immunity clears - entire infection moves too fast for Ab to be produced/effective
Why isn’t there a rhinovirus vaccine?
Too many strains - recombination
What bug causes flu?
Orthomyxoviridae
Orthomyxoviridae genetics: - or + ss or ds Helical or icosahedral capsid Enveloped?
-ssRNA in 8 indep segments
Helical
Enveloped
Where does Orthomyxoviridae replicate in host cells?
Nucleus
Which proteins are present on Orthomyxoviridae envelope?
HA
NA
Describe flu nomenclature:
A/California/07/2001 (H1N1)
A = type of flu (A, B or C) Cali = where first isolated 07 = isolate # 2001 = year of isolation H1N1 = major HA & NA type
What receptor does flu bind to enter host cells?
HA + sialic acid
How is the flu genome release after being endocytosed?
Endosome turns ACIDIC via M2 channel
HA triggered virus/endosome membrane fusion
Release genetic material alone