Viral Pathogenesis Flashcards
7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Viral Pathogenesis flashcards as text
What is the mechanism by which some viruses cause cell transformation and tumor formation?
Answer: Viral oncoproteins inactivate tumor suppressor proteins such as p53 and Rb
Oncogenic viruses like HPV produce proteins (E6 and E7) that inactivate p53 and Rb respectively, removing critical checkpoints that prevent uncontrolled cell division.
Which innate immune mechanism is the FIRST line of antiviral defense activated upon viral entry into a cell?
Answer: Production and release of type I interferons (IFN-α/β)
Pattern recognition receptors (e.g., RIG-I, MDA5) detect viral RNA within infected cells and trigger rapid production of type I interferons that establish an antiviral state in neighboring cells.
A patient presents with a vesicular rash following a dermatomal distribution decades after childhood chickenpox. What is the pathogenic mechanism?
Answer: Reactivation of latent VZV from sensory ganglia triggered by immunosuppression or stress
Varicella-zoster virus establishes latency in dorsal root and cranial nerve ganglia after primary infection; reactivation causes herpes zoster (shingles) along the affected dermatome.
Why is co-infection of a single cell with two different influenza strains particularly concerning from a public health perspective?
Answer: Genetic reassortment between the two strains can produce a novel virus with pandemic potential
Influenza's segmented genome allows mixing of RNA segments (reassortment) between two strains in a co-infected cell, potentially generating a new subtype with novel surface antigens — the basis of antigenic shift.
What does the term 'viral quasispecies' refer to in the context of RNA virus pathogenesis?
Answer: A dynamic population of closely related but genetically distinct viral variants present in a single host
Due to error-prone replication, RNA viruses exist as a cloud of related mutant sequences (quasispecies) that collectively enable adaptation, immune escape, and drug resistance.
How does the blood-brain barrier (BBB) influence the pathogenesis of viral encephalitis?
Answer: The BBB normally restricts viral access, but some viruses breach it via transcytosis or infected immune cells
Some neurotropic viruses (e.g., West Nile, herpes encephalitis) cross the BBB via transcytosis through endothelial cells or by infecting monocytes that traverse into the CNS (Trojan horse mechanism).
Which concept explains why some individuals infected with a pathogenic virus remain asymptomatic while others develop severe disease?
Answer: Viral inoculum size, host genetic factors, and immune status collectively determine disease outcome
Disease severity results from a complex interplay between viral factors (strain, dose) and host factors (age, genetics such as HLA type, immune status, and comorbidities).