Download Chain of transmission - PublicHealthOntario.ca

Best Practices for Environmental Cleaning
Module 1 – Chain of Transmission
Learning Objectives
At the end of this session you will be able to:
1. Explain the importance of environmental cleaning
2. Describe the general principles of transmission of
infectious agents
3. Suggest some strategies to break the chain of
transmission
2
Background
•
Healthcare Associated Infections (HAIs) occur as a
result of health care interventions in any health care
setting
•
HAIs are a client/resident/patient safety issue and
represent a significant adverse outcome of the
healthcare system
•
The environment around the client/patient/resident
influences the incidence of infection
 Cleaning and disinfection reduces the numbers of
microorganisms in the healthcare environment
•
The goal of cleaning is to keep the environment safe
for clients/residents/patients, staff and visitors
3
Chain of Transmission
Infection prevention strategies are aimed
at “breaking the chain” at one of its links
4
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
5
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
6
Infectious Agent – The Germ
• Germs are everywhere!
• Bacteria

MRSA, VRE, C. difficile, Salmonella, Group A Streptococcus
• Viruses

Influenza, Hepatitis B, HIV
• Parasites

Giardia, Malaria
• Fungi

Candida, Aspergillus
* The State of Queensland
7
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
8
Reservoir – Hiding Places
Place where infectious agent can survive, but may or may not
multiply:

People

Cases and carriers

Food


Environment (water, solutions)
Animals
9
You cannot tell by looking . . .
10
You cannot tell by looking . . .
11
You cannot tell by looking . . .
12
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
13
Portal of Exit – Way OUT
How an infectious agent gets out of reservoir
• Human portals of exit:
• Respiratory system
• Genital and urinary tracts
• Intestinal tract
• Skin/mucous membrane
• Trans-placental
• Blood
14
Learning Checkpoint
15
Learning Checkpoint
Which of the following are reservoirs for germs?
a)
An individual with a cold
b)
Outdated cleaning solution
c)
Visiting pets
d)
All of the above
16
Learning Checkpoint Answer
• The correct answer is d – All of the above are
reservoirs for transmission of germs.
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
18
19
Transmission – Getting Around
Direct
Indirect
CONTACT
20
Transmission – Getting Around
<2 metres
Droplet
21
Transmission – Getting Around
Airborne transmission
<2 metres
Droplet
22
Transmission – Getting Around
VEHICLE
23
Transmission – Getting Around
Vectorborne
24
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
25
Portal of Entry – Way IN
• Non-intact skin
• Mucous membranes
• Respiratory system
• Gastrointestinal system
• Genitourinary system
Aerosol image: http://staff.vbi.vt.edu/pathport/pathinfo_images/Mycobacterium_tuberculosis/AerosolTransmission.jpg
26
Learning Checkpoint
27
Learning Checkpoint
What is the most common mode of
transmission for infection?
a.
Droplet
b.
Airborne
c.
Contact
d.
Respiratory
28
Learning Checkpoint Answer
• The correct answer is c – The majority of
infections are spread through direct and
indirect Contact
Infectious Agent
The Germ
Susceptible
Host
Next Sick
Person
Reservoir
Hiding Places
Chain of
Transmission
Portal of Entry
Way In
Portal of
Exit
Way Out
Means of
Transmission
Getting Around
30
Susceptible Host
The Next Sick Person
• Anyone who lacks immunity or has reduced
resistance to a particular infectious agent
31
Host Characteristics
•
•
•
•
Age
Disease history
Underlying illness
Lifestyle
32
When you return to your job, what will you
do differently as a result of this session?
33
Thank You!
34
Image Sources – Module 1
• Getty Images used in:
 Slides 9, 10, 11, 12, 20 & 22
 Quiz question 7
• iStock photos used –
 Slides 19 & Quiz question 7 – PersonSneezingiStock_000003466751
 Slide 24 – Mosquito_iStock_000018469709
• Microsoft Clipart used in:
 Slides 12, 15 & 27
 All quiz answers
• All other images are © PHO 2013