Herpesviridae

Question 1

Herpes

Answer 1

Latency infection and capcacity for recrudescence is key to its success

Question 2

Herpesviridae structure

Answer 2

dsDNA

- complex envelope and complex structural components

Question 3

What properties can be expected of a virus w complex structural components?

Answer 3

• very good at identifying target cells
• highly specific interaction
• lipids in envelope is going to get virus in cell
• cloak that helps manipulate host cell trying to reject foreing material

Question 4

Genome replication and virion assembly

Answer 4

1. early genes and microRNAs control host cell and regulate innate immune respinse
2. orderly expression of genes result in productive infections and many progeny virions OR
3. Herpes genome can exist as an episome replicated by host cell machinery which allows latency (genetic switch determines infection or latency)

Question 5

What are the advantages for a virus to become latent (not replicating itself) and recrudescent (changing from latent state)?

Answer 5

• Specialises from one host to new host
• different conditions in new host
• stress occurs when animals are mixed into new host
• virus waits for stress

Question 6

Latency and recrudescence

Answer 6

• latency (evades immune response)
• latent state achieved by targeting correct tissues (neurons, immune cells)
• Cold sore is a neuronal latency. Stress –>mucosal surfaces–> more easily find way to new host
• herpes genome as a circular episome in neurologic or immune cells

Question 7

Generalisations of herpes

Answer 7

• large and complex virion structure
• dsDNA genome w many genes and microRNAs
• effective control of host and ability to control its own replicate state- uses its own machinery (drug targets)
• latency and recrudenscence enables long term persistence in stable host population

Question 8

Alphaherpesvirinae

Answer 8

• Human herpesvirus 1 (cold sores)
• Human herpesvirus 2 (chicken pox)
• rapid replication, lytic infection of cells, latency most common in nerve ganglia

Question 9

Betaherpesvirinae

Answer 9

• Human herpesvirus 5
• slow repliction, enlargement of infected cells, latency most common in luecocytes
• Elephant endotheliotropic virus 1

Question 10

Gammaherpesvirinae

Answer 10

• Human herpesvirus 4

- variable replication rate, often not lytic, latency most common in lymphoid

Question 11

Prevention

Answer 11

• Vaccination
• biosecurity; prevent naiive pop from being exposed
• eradication; disease surveillance w culling

Question 12

POMS

Answer 12

Pacific oyster mortality synrome