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Basic Infection Control for Property Management - Chapter 2: Concepts of Infectious Diseases

Hi colleagues
This is the latest version of infection control guideline 
and cleaning procedure instruction
And the other one is the response plan
for suspected novel / severe emerging infectious disease
I understand that many of you are experienced
but I still hope you can familiarise yourselves with the contents
especially we have a new member here
We should look out for each other
Prevention of infectious diseases? 
You mean wearing mask when having a cold?
It is not only about mask wearing
You also have to wash hands, and wash frequently
How about diarrhoea after eating unclean food? Is it an infectious disease?
You mean food poisoning?
All of you are correct, but infectious diseases are not that simple
Let's watch the video to know more
Dr Leo Lui, Associate Consultant, Infection Control Branch, Centre for Health Protection
Dr Lui, could you tell us more about infectious diseases?
KJ, infectious diseases are diseases that can be spread directly 
or indirectly to humans to cause an infection
These diseases are caused by pathogens 
(including bacteria, viruses, fungi and parasites) invading our bodies
The pathogens multiply in the human body and cause damage to normal cells,
death can ensue in serious situations
These pathogens can be transmitted from an infective source 
(e.g. patients, animals) to a person through various routes
causing the person to be infected and fall ill
What are the routes of transmission for an infectious disease?
A number of factors must be present simultaneously for a disease to acquire infectivity
They include pathogens (i.e. infective microorganisms)
source of infection, mode of transmission and susceptible host
This process is known as the "chain of infection"
Routes of transmission can be broadly categorised as contact, droplet and airborne 
Certain infectious diseases can be transmitted by more than one route 
Theoretically, transmission of infectious diseases 
can be prevented by interrupting the chain of infection
Contact is the most common route of transmission
Transmission through direct contact refers to person-to-person spread of pathogens
via direct physical contact, such as by hands
Transmission through indirect contact 
occurs by coming into contact with contaminated environment or object
such as sharing of towel
Most of the multi-drug resistant organisms
and scabies, which can cause severe skin itchiness
are examples that are transmitted by the contact route 
Droplet transmission occurs when infectious droplets
deposit on the mucous membrane of eyes, nose and mouth
These particles are usually larger than 5 micrometres in size 
hence they do not remain suspended in the air for a prolonged period of time 
and normally do not travel beyond the distance of 1 to 2 metres from the source person
When the source person coughs, talks or sneezes
the infectious droplets are generated
Influenza is an infectious disease transmitted by the droplet route
When airborne droplet nuclei (usually smaller or equal to 5 micrometres in size) 
containing pathogens remain suspended in the air for a prolonged period of time
and are inhaled into our respiratory system
airborne transmission will result
Examples of infectious diseases transmitted by the airborne route
 include tuberculosis, chickenpox and measles
Apart from the 3 routes mentioned
other routes of transmission include bloodborne transmission, sexual transmission
mother-to-child transmission and vector-borne transmission, etc