Lecture 1.2 - Introduction to Infection

Question 1

What causes disease in infections?

Answer 1

Microbial multiplication leads to toxin production and a host response, both of which result in disease

Question 2

Give examples of routes via which infections may be passed on

Answer 2

Direct from source to patient
Via vector
Via environment
Via animals
Migration of normally harmless microbes to another site in the body

Question 3

What is meant by the term “microbiota”?

Answer 3

The sum of all the microorganisms present in a certain place, e.g. the skin

Question 4

Give examples of horizontal routes of transmission

Answer 4

• Contact - direct and indirect
• Inhalation - droplets and aerosols
• Ingestion

Question 5

By what steps do microorganisms cause disease?

Answer 5

1) Exposure
2) Adherence to body surface
3) Invasion
4) Multiplication
5) Dispersion
6) Virulence factors
7) Host cellular damage

Question 6

What is meant by “virulence factors”?

Answer 6

Mechanisms by which a particular microorganism causes disease

Question 7

What are exotoxins?

Answer 7

Chemicals released by microbes into the local environment

Question 8

What are endotoxins?

Answer 8

Part of the structure of a microbe which the body has learnt to recognise as an infection

Question 9

Give some pathogen factors that determine the extent of the disease

Answer 9

Virulence factors
Inoculum size
Antimicrobial resistance

Question 10

Give some patient factors that determine the extent of an infection

Answer 10

Site of infection

Co-morbidities

Question 11

Give some examples of bacteriology

Answer 11

Microscopy
Culture
Antigen detection
Nucleic acid detection

Question 12

Give some examples of virology

Answer 12

Antigen detection
Antibody detection
Nucleic acid detection

Question 13

What is an infection?

Answer 13

Invasion of a host’s tissues by microorganisms, resulting in disease.