Introduction to Viruses Flashcards Preview

Principles of Disease 16 > Introduction to Viruses > Flashcards

Flashcards in Introduction to Viruses Deck (12)
1

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

2

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.

3

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

4

Whats the diameter of a typical virus?

20 – 400 nm diameter

5

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

6

List possible routes of transmission

Blood-borne
Sexual
Vertical
Faecal-oral
Droplet
Airborne
Close contact
Vector borne
Zoonotic

7

What are the 4 possible outcomes of infection?

Clearance
Chronic infection
Latent infection
Transformation

8

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.

9

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

10

How would you detect whole organisms?

• Microscopy
• Cell culture

11

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

12

How can you prevent viral infection?

• Immunisation
• Vaccination
• Passive immunisation with immunoglobulin
• Prophylactic treatment post exposure
• Infection prevention & control measures
• Isolation of symptomatic patients
• Personal protective equipment
• Safe use and disposal of sharps
• Blood / tissue / organ screening
• Antenatal screening