Viruses Introduction

Question 1

Give three possible shapes of viruses

Answer 1

Icosahedral
Helical
Complex

Question 2

What are viruses classified by? (taxonomy)

Answer 2

Shape
Symmetry
Envelope presence/absence
Genome structure
Replication mechanism

Question 3

Differentiate droplet and airborne transmission of viruses

Answer 3

Droplet - large particles that fall within a short distance of the source (low-risk)
Airborne - can travel further in the environment

Question 4

Give 4 possibilities resulting from a viral infection

Answer 4

Clearance with short/long/no immunity
Chronic infection
Transformation (long-term; altered gene expression)
Latent infection

Question 5

How can viral infection give rise to cancer?

Answer 5

Cell cycle control is modulated
Apoptosis is affected
Can lead to uncontrollable cell proliferation
e.g. Hodgkin’s lymphoma

Question 6

What ways are viral infections detected?

Answer 6

Partial organism identification by PCR

Antibody/antigen presence indicating an immune response taking place

Question 7

Name four different methods of viral infection therapy

Answer 7

Antiviral (all virustatic)
Prophylaxis
Pre-emptive treatment
Suppressive treatment

Question 8

Give three methods of preventing viral infection

Answer 8

Immunisation via vaccination/immunoglobulins
Prophylactic treatment
Screening

Question 9

Give three conditions which must be satisfied for a virus to possible be eradicated

Answer 9

No animal reservoir
Possible practical intervention
No chronic carrier state
e.g. smallpox/polio