Outbreak Basics

Preparing for an outbreak

  • Evaluate and update outbreak policies and procedures annually in accordance with evidence-based practices or prevailing practices.
  • Ensure staff, students and volunteers receive routine education and training on outbreak management and control.

What is an outbreak?

  • An outbreak is generally an increase in the number of infections above the number normally expected for that setting over a defined period of time.
  • The Ontario Ministry of Health and Long-Term Care has specific outbreak definitions. They are defined as follows:
Respiratory Outbreak
Confirmed Outbreak: 3 or more cases within 48 hours in a specific area OR more than 2 units having a case within 48 hours OR 2 cases with one being lab confirmed
Suspect Outbreak: 2 cases within 48 hours in a specific area OR more than one unit having a case within 48 hours
Enteric Outbreak
Confirmed Outbreak: 3 or more cases within a 4 day period in a specific area OR 3 or more units or floors having a case within 48 hours
Suspect Outbreak: 2 cases in a specific area within 48 hours

What are outbreak case definitions?

Outbreak case definitions are a set of criteria for determining who should be classified as a case. The definition is developed based on the clinic information and epidemiological information related to time, place and person.

Respiratory Case
A resident or staff with 2 or more new respiratory symptoms such as fever, cough, runny nose, nasal congestion, sore throat/hoarseness.  The respiratory case definitions should be developed for each outbreak as symptoms will vary based on the pathogen involved.
Enteric Case
A resident or staff with 2 or more episodes of vomiting and/or diarrhea or a combination of vomiting and diarrhea within 24 hours or lab confirmation of a pathogen with one symptom.

When to call Public Health

If you suspect an outbreak, contact Southwestern Public Health to discuss outbreak management and control with a member of the Infectious Diseases team.

Monday - Friday 8:30 am - 4:30 pm After-hours and holidays
St. Thomas Site: (519) 631-9900 ext. 1232 St. Thomas Site: (519) 631-9900 ext. 0
Woodstock Site: (519) 421-9901 ext. 3500 Woodstock Site: (519) 533-0131


Last Updated: January 4, 2019