Flashcards in Introduction to Viruses Deck (12)
Explain the basic classification and characterisation of viruses.
Viruses are classified according to:
o Host Range
o Virion Structure and Morphology
o Structure and replication of virus genome nucleic acid
Outline the principles of viral culture.
Since viruses require living cells to live, all cultures must take place in cell lines, tissues or intact animals. The cells are grown in a nutrient containing medium, in at atmosphere with 5% CO2.
Describe examples of human virus infection of major importance.
o Respiratory - Influenza A Virus, Rhinovirus, Respiratory Syncytial Virus
o Gastrointestinal - Rotavirus
o Neurological - Enterovirus, Herpes Simplex Virus
o Tumours - Papillomavirus, Retroviruses
Whats the diameter of a typical virus?
20 – 400 nm diameter
Describe the basic structure of a virus
• Icosahedral: 20 faces, each an equilateral triangle
• Helical: protein binds around DNA/RNA in a helical fashion
• Complex: neither icosahedral or helical
List possible routes of transmission
What are the 4 possible outcomes of infection?
What is viral latency?
Virus latency (or viral latency) is the ability of a pathogenic virus to lie dormant (latent) within a cell, denoted as the lysogenic part of the viral life cycle. A latent viral infection is a type of persistent viral infection which is distinguished from a chronic viral infection.
Describe some mechanisms that viral infection can lead to cancer
o Modulation of cell cycle control (driving cell proliferation)
o Modulation of apoptosis (prevention of programmed cell death)
o Reactive oxygen species mediated damage (some persistent viral infections can cause persistent inflammatory processes which lead to cancer via reactive oxygen species
How would you detect whole organisms?
• Cell culture
What can antiviral therapy be used for?
• Prophylaxis (to prevent infection)
• Pre-emptive therapy (when evidence of infection/replication detected, but before symptoms are apparent)
• Overt disease
• Suppressive therapy (to keep viral replication below the rate that causes tissue damage in an asymptomatic infected patient