Mechanism of viral infection and pathogenesis

Question 1

Distinguish between infection and disease

Question 2

Why do most viruses were exposed to dailt not infect us?

Question 3

How does site of microbe entry vary?

Question 4

Name a few common virus diseases of man?

Question 5

Name a few disease eradicated by vaccines

Question 6

When does disease symptoms occur in acute viral infections?

Answer 6

Viral load is at its peak

Question 7

Why do acute infections not reoccur

Answer 7

generally develop long lasting immunity from first exposure

Question 8

name a few common acute viral infections

Answer 8

Common cold
Measles
Ebola
Smallpox

Question 9

What are the 4 general patterns of viral infection

Question 10

Give an example of a latent/reactivation infection

Answer 10

Herpes virus
- life long infection, controlled by immunity
Chickenpox by varicella zoster virus, reactivates into shingles

Question 11

How do viruses establish latent infection without being detected?

Answer 11

Virus transits up peripheral nerve and can transit back down them when virus in the neurone is reactivated

Question 12

Give an example viruses causing persistant present of active immune response

Answer 12

HIV - retrovirus
HCV - flavivirus
Measles in certain cases
Congenital rubella

Question 13

How are viral levels controlled in persistent infection

Answer 13

Active host immunity

Question 14

When does congenital rubella infect?

Answer 14

In utero via placenta of pregnant woman causing baby to be born immunotolerant and virus continues to replicate infecting all foetal organs and damaging neonatal tissue

Question 15

How does a virus infection lead to disease?

Question 16

What are inapparent infection? + give an example

Answer 16

Asymptomatic e.g. most polioviruses

Question 17

When are infection inapparent?

Answer 17

Virus must be non-cytopathic and host-adapted

Question 18

What does pathogenesis of virus result from?

Answer 18

Cell and tissue damage caused by viral infection, damage usually limited by host’s immune system

Question 19

What cytopathic damage does EBOLA cause?

Question 20

What cytopathic damage feos Influenza A virus cause?

Question 21

What cytopathic damage does RSV cause?

Question 22

What is immunopathology?

Question 23

Give an example of immunopathology disease

Question 24

Why is there damage in HCV (hepatitis C virus)?

Question 25

What are the features of HCV?

Question 26

What are the types of dengue fever?

Question 27

What is dengue shock syndrome (DSS) and what is the greatest risk that results in DSS?

Question 28

Why does previous infection with diff serotype of dengue virus result in DSS?

Question 29

What is RSV?

Question 30

How does severity of disease change due to adaptive immunity?

Question 31

What is the pathology of Flu?

Question 32

Why are we not protected from flu through flu vaccine (influenza)?

Question 33

What part of immunity helps in next seasonal flu strain despite antigenic drift?

Question 34

Why are pandemic flu’s (certain influenza strains) deadly?

Question 35

Why will vaccines not help prior to pandemic flus unlike seasonal flus?

Question 36

What does the outcome of an infection depend on?