epidemeology and pathogenesis of viral disease

Question 1

What can be used to study epidemiology

Answer 1

Mode of transmission
Age
Gender
Ethnic background/ country of origin
Travel history
Occupation
Season
Underlying medical conditions

Question 2

What are the 6 horizontal routes of transmission

Answer 2

Direct contact (secretions, blood)
Respiratory
Contaminated innaimate objects
Faecal/oral
Inset vector
Zoonoses

Question 3

What is vertical transmission

Answer 3

Mother to foetus transmission (transplacental)

Question 4

What is the cycle of infection

Answer 4

Entry
Primary site of replication
Spread within the host
Secondary site(s) of replication
Shedding
Transmission

Question 5

How can viruses enter the body

Answer 5

-mucous membranes or skin
Respiratory tract
Oral - GI tract
Sexual
Ocular
Percutaneous (wounds etc)

Question 6

What is the course of an acute infection

Answer 6

Virus detected by body, immune reaction to stop and clear virus over the course of few days or weeks

Question 7

What is the course of a chronic infection

Answer 7

The immune system is unable to clear virus infection so virus is constantly produced

Question 8

What is the course of latent infections

Answer 8

Does not have any active pathogens at certain period but can become reactivated and cause disease (usually herpes)

Question 9

What is the effect of abortive infection on cells during infection

Answer 9

Restriction factors block or limit viral replication

Question 10

What are the effects of infection on cells

Answer 10

Cytopathic effect - cpe
Host cell protein translation switched off
Apoptosis (cell defence/ avoidance by virus)
Transformation
Pattern recognition receptors (PRRs)

Question 11

What is transformation of a cell

Answer 11

Immortalisation of cell - tumours

Question 12

What do pattern recognition receptors (PRRs) trigger

Answer 12

Innate immune response
Immune evasion
Production of interferons

Question 13

What factor causes the host protein translation being shutoff

Answer 13

Cleavage of ‘cap binding complex’ (CBC)

Question 14

What is the ‘cap binding complex’ (CBC) involved in eukaryotes

Answer 14

Binding the m7G cap structure at the 5’ end of all eukaryotic mRNAs during initiation of translation

Question 15

How does influenza use host protein translation shutoff

Answer 15

The virus steals mRNA cap allowing translation of viral mRNA

Question 16

What are the types of transforming viruses

Answer 16

Human papillomavirus (HPV)
Retroviruses
Herpesviruses
Hepatitis B and hepatitis C virus

Question 17

What role do interferons play during infection

Answer 17

Role in inhibiting virus infection in cells

Question 18

What are strategies used by viruses to block aspects of innate response

Answer 18

Secreted modulators
Modulators on infected cell surface
Stealth/latency
Antigenic hypervariability
Block adaptive immune response
Inhibit complement
Interfere with pattern recognition receptors (PRRs)
Block interferon and/or inflammatory cytokines

Question 19

How do viruses use modulators on infected cell surface to their advantage

Answer 19

Mimics antagonists of immune signalling