Pathogen and Host

Question 1

viral pathogenesis

Answer 1

study of how viral infection leads to disease

Question 2

what methods can viruses use to go from infection to disease

Answer 2

1. cell destruction
2. immunopathogenic (alter immune system)
3. change to cellular gene expression

Question 3

pathogen

Answer 3

an organism which can cause disease

Question 4

what features does a pathogen require to be classed as a pathogen

Answer 4

1. present in all cases of the disease

2. can be cultured outside the body for multiple generations

Question 5

commensal

Answer 5

organism which is part of the normal flora

Question 6

innate immunity

Answer 6

non-specific e.g. skin, phagocytes

Question 7

acquired immunity

Answer 7

specific response to antigen. immunological memory created

Question 8

colonisation

Answer 8

microorganisms present but don’t cause disease

Question 9

asymptomatic infection

Answer 9

someone is a carrier but is not showing symptoms

Question 10

pathgenicity

Answer 10

ability of an organism to cause disease in a host

Question 11

example symptoms

Answer 11

inflammation
pain
pyrexia
tachycardia
rigor
increased WBC count

Question 12

characteristics essential to cause disease in host

Answer 12

infectivity - established in host

virulence - harm in host

Question 13

endotoxin

Answer 13

• component of gram negative bacterial cell wall
• lipopolysaccharide
• attached to microorganism

Question 14

exotoxin

Answer 14

• released by micro-organisms

- not attached to micro-organism

Question 15

enterotoxin

Answer 15

exotoxin which acts on the GI tract

Question 16

sites of viral entry

Answer 16

• respiratory tract
• alimentary (digestive) tract
• urinogenital tract
• skin
• arthropod
• conjunctiva

Question 17

features of acute viral infections

Answer 17

• localised to a specific site of the body
• rapid onset of disease
• brief period of symptoms
• resolution within days

Question 18

example of how virus induces tumours

Answer 18

HPV - infects the cell, integrating into the cellular genome, causing a change in gene expression, which causes uncontrolled cell proliferation and tumour formation

Question 19

humoral immunity

Answer 19

mediated by macromolecules found in extracellular fluids

• mostly bacterial infection
• involves antibodies
• acute inflammation

Question 20

cell mediated immunity

Answer 20

does not involve antibodies, but rather involves;

• the activation of phagocytes
• antigen-specific cytotoxic T-lymphocytes