1. Or How infection is caused
The Chain of Infection Or
How infection is caused

2. Recap! Infections are caused by the entry of a micro-organism
Bacteria, viruses, fungi
Infection may be acute or chronic
Infection may be localised or systemic
Normal flora & transient flora

3. The Chain of Infection Identifies: The micro-organism The reservoir
Portals of exit
Methods of transmission
Portals of entry
Hosts

5. The Micro-organism Disease causing organisms include Bacteria Viruses
Fungi

6. Reservoir
This refers to anywhere an infectious organism can survive, grow or multiply
Includes:
Plants
Animals
Soil
Water
Medical equipment

7. Reservoir The human body is the most common reservoir! Carrier
A person who carries and can spread disease

8. Portals of exit The way the infectious organism leaves the body
Body fluids including blood
Coughing
Sneezing

9. Methods of transmission
Four methods
Contact
Direct – person to person
Indirect – person to object
Droplet – e.g. sneeze
Airborne – longer distance & greater time
Ingestion – contaminated food or water
Vector – via living creatures or insects

10. Portals of entry Respiratory tract Ears and eyes Gastro-intestinal
Genito-urinary tract
Broken skin

11. Hosts Barriers are compromised e.g. broken skin Imunocompromised
Level of susceptibility depends on
Age: Infants & elderly at greater risk
Nutritional status
Stress
Environment
Pre-existing conditions

12. Finally…
Mrs Price