The Chain of Infection
As healthcare
professionals, it is
important to
understand two
things about
infection:
1.How infection can be
transmitted
2. How to break the infection
chain
There are six
links
in the chain of
infection :
The Chain of Infection
Infectious
agent
Reservoir
host
Susceptible
host
Portal of Exit
Portal of Entry
Route of
transmission
1st - The Infectious Agent
Pathogen
bacteria
virus
fungus
2nd - The Reservoir Host
Where the microbe lives
and grows.
People
animals
Water
food
3rd - The Portal of Exit
-Where the microbe leaves (exits)
the host
Respiratory System
Gastrointestinal System
Urinary & Reproductive Tracts
Skin Barrier/Blood
Non-intact skin
4th - The Route of
Transmission
-HOW the pathogen
gets from the
reservoir host to the
new host
Flu virus
How do I get to Mr.
Smith’s lungs?
3 Main Methods or Routes of
transmission in health care facilities:
2. Direct Contact
1. AIR
3. Indirect Contact
th
5 -
Portal of Entry
The Portal of Entry is how the
pathogen enters the host’s
body. Usually the same as the
Portal of Exit.
6th - The Susceptible Host
-the person that the pathogen
enters
A susceptible person is someone
at higher risk for developing an
infection
Susceptible Hosts
•
•
•
•
The elderly
People with low immune systems,
Health care workers
Infants
What are ways can you think of to
prevent the transmission of germs?
• Power Point adapted from:
• www.cte.unt.edu/health/curriculum/Chain_
of_Infection.ppt
• Some images from Google Images