Virology 2 Flashcards
What is the Baltimore classification of Herpes Simplex Virus (HSV)?
Group I: dsDNA virus.
What are the key glycoproteins used by HSV for host cell entry?
gB, gC, gD, gH, gL.
What is antigenic drift in Influenza virus?
Gradual accumulation of mutations in viral RNA leading to new strains.
What is antigenic shift in Influenza virus?
Reassortment of RNA segments from different influenza strains, creating novel viruses.
How does Norovirus bind to host cells?
Binds to histo-blood group antigens on epithelial cells.
HSV can remain latent in
neurons and reactivate later.
Influenza virus has 8 RNA segments encoding different
proteins.
Norovirus is highly contagious and a major cause of
gastroenteritis.
HSV-1 primarily causes oral lesions, while HSV-2 is more associated with
genital herpes.
Antiviral drugs like acyclovir target
HSV DNA polymerase.
HSV-1 and HSV-2 infect only neurons.
False – they also infect epithelial cells.
Influenza virus undergoes both antigenic drift and antigenic shift.
True
Norovirus is an enveloped virus.
False – it is non-enveloped.
HSV replication occurs entirely in the host cytoplasm.
False – occurs in the nucleus.
The lipid envelope of HSV gives it a characteristic ______________ appearance.
Fried egg
The enzyme ______________ is used by Influenza virus to cleave sialic acid from host cells.
Neuraminidase
HSV replication uses a mechanism called ______________ replication.
Rolling circle
Norovirus infections are more common in the ______________ season.
Winter
Which glycoprotein of Influenza virus binds to host receptors?
a) Neuraminidase
b) Haemagglutinin
c) VP1
d) gD
Answer: (b) Haemagglutinin
Which antiviral drug is commonly used to treat HSV infections?
a) Oseltamivir
b) Acyclovir
c) Zanamivir
d) Remdesivir
Answer: (b) Acyclovir
Which viral characteristic makes Norovirus so contagious?
a) Large genome
b) High mutation rate
c) Low infectious dose
d) Envelope instability
Answer: (c) Low infectious dose
A patient presents with recurrent cold sores. What is the likely virus, and what laboratory test can confirm the diagnosis?
Likely virus: HSV-1. Confirmatory test: PCR of vesicle fluid targeting glycoproteins like gB and gD.
A new strain of Influenza emerges with segments from two different strains. What mechanism caused this?
Antigenic shift due to reassortment of RNA segments.
An outbreak of severe vomiting and diarrhea occurs in a nursing home. What is the likely pathogen, and what factors contribute to its rapid spread?
Likely pathogen: Norovirus. Factors: Low infectious dose, high environmental stability, and easy person-to-person transmission.
Latency:
A phase where the virus remains dormant in host cells.
Rolling Circle Replication:
Method of DNA replication used by HSV.
Neuraminidase:
Enzyme that helps Influenza virus release from host cells.
Histo-blood Group Antigens:
Receptors for Norovirus attachment.
Antigenic Shift:
Major genetic change due to viral genome reassortment.
