Year 1 Viruses

Question 1

General Properties?

Answer 1

• Small
• Require a host
• Variety of shapes
• No biological machinery

Question 2

Structure?

Answer 2

• Nucleic acid core
• Capsid
• Forms vary (helical or icosahedral)
• Some have envelope or tails

Question 3

Replication?

Answer 3

Target specific tissue/cell type (tissue tropism)

1. Attachment
2. Penetration
3. Synthesis of nucleic acid and protein
4. Assembly and packaging
5. Release (lysis) of virons

Question 4

Routes of transmission?

Answer 4

• Respiratory e.g. influenza A
• Faecal-oral e.g. enterovirus
• Blood-borne e.g. Hepatitis B
• Sexual e.g. HIV
• Vector (animal, insect) e.g. rabies

Question 5

Antiviral drugs:

need to:

methods of action??

Most effective when…

Answer 5

• Be able to enter cells infected
• Interfere with viral nucleic acid synthesis/regulation
• Interfere with binding ability
• Some drugs stimulate body’s immune systems

Effective in patients with competent immune systems - works WITH the immune system to eliminate/suppress

Question 6

Example of Nonretroviral Neuraminidase Inhibitors? Use?

Common side effects?

Answer 6

Tamiflu - influenza A + B

nausea, vomiting

Question 7

Antiretroviral Drugs:

What is HAART?

What is an RTI?

Examples?

Answer 7

Highly Active Antiretroviral Therapy - 3+ medications as a cocktail to reduce viral load

RTI = Reverse Transcriptase Inhibitor - prevents new viral DNA

e.g.
abacavir, tenofovir, didanosine