Germ Illustration

How Infection Spreads

Understanding is the first step to controlling the spread of infection. Review the following information with your staff and, if possible, with parents.

  • Infections are illnesses that are caused by bacteria, viruses or other microorganisms.
  • These microorganisms are found in body excretions (stool) and secretions (tiny droplets produced by breathing, coughing or sneezing).
  • They spread from one person to another in different ways. Some are spread through the air; others through contamination of toys and surfaces; still others only through blood contact.
  • Children can become ill whether or not they are in a child care centre. But they are more likely to become ill when they spend their day with many other children.
  • People can spread some infections without being sick themselves. Several infections are contagious before any symptoms appear or after the acute illness is over; others may not have symptoms at all.

Three factors must be present for an infection to occur. These are:

  • Infectious agent (e.g. bacteria, virus, fungi).
  • Host (e.g. person).
  • Mode of transmission, method of spread (e.g. contaminated hands).

To reduce the spread of infection in the child care centre, you must eliminate the infectious agent and/or the mode of transmission.

Infectious Agents

  • Types of microorganisms include bacteria, viruses, and fungi.
  • Bacteria and viruses are responsible for enteric and respiratory illnesses.
  • Bacteria and viruses are too small to be seen by the naked eye.
  • Not all bacteria  cause illness.
  • Antibiotics are only effective against bacteria.
  • Sometimes only a few organisms are needed to cause illness.
  • Organisms can survive on surfaces for hours, days and even weeks.


  • The host can be a child, staff or any person in the centre.
  • Immunization is an important method for preventing illnesses.
  • A previous infection may offer future protection to the host when they are exposed to the same infectious organism (natural immunity).

Organisms can be Spread Through (Modes of Transmission):

  • Direct contact with an infected person (e.g. skin infections can spread by skin to skin contact).
  • Contact with a contaminated surface (e.g. door handle, table top).
  • Air (e.g. sneezing).
  • Eating contaminated food and drinking unsafe water (e.g. improperly refrigerated food or improperly cooked food).
  • Bites from infected insects or animal.

Effective infection control practices such as proper hand hygiene, diaper changing, cleaning and disinfecting surfaces and exclusion of ill children and staff will reduce the spread of infection in the centre.

Last modified: February 19, 2020