INFECTIOUS DISEASE AND ZOONOSES - Overview

Question 1

List five main causes of infectious disease

Answer 1

Bacteria
Viruses
Fungi
Parasites
Prion proteins

Question 2

What is epidemiology?

Answer 2

The study of the spread of infectious diseases within a community or population

Question 3

How can infectious diseases be spread?

Answer 3

Patients with infectious disease
Symptomless carriers
Zoonoses
Food, water, soil
Faecal contaminants
Reservoirs

Question 4

What is pathogenesis?

Answer 4

The development of disease

Question 5

List the steps of pathogenesis

Answer 5

Acquisition
Colonisation
Invasion
Spread
Damage
Resolution (possibly)

Question 6

What is transient colonisation?

Answer 6

The presence of a pathogen in or on a host which grows and divides for a temporary period of time

Question 7

What is prolonged colonisation?

Answer 7

The presence of a pathogen in or on a host which grows and divides for a prolonged period of time

Question 8

Describe viral pathogenesis

Answer 8

1. Virus invades and subverts the metabolic activity of the host cell to re-direct the cell into synthesising net virtual components
2. Viruses usually kill the cell the have infected when the viral components are release
   
   • causes lesions/disease at the disease site
   • permanents/non-dividing tissue cannot be replaced causing permanent damage
   • Viruses can also induce immunopathology

Question 9

Describe fungal pathogenesis

Answer 9

1. Fungal spores from the environment invade the body
2. Fungal spores grow into fungal hyphae
3. Fungal hyphae can:
   
   • digest keratinised tissue (superficial infection)
   • cause mucous membrane infection
   • cause blood-borne infection

Question 10

What is immunopathology?

Answer 10

Disease caused as a consequence to the host’s immune response to an invading pathogen