Something you ate? Episode 2: Tracking the source

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Epidemiology Investigation
Transcript - Epidemiology Investigation

Narrator
The Government of Canada and food industry maintain high standards for food safety practices. However, no system is perfect and outbreaks of enteric illness happen from time to time. Identifying outbreaks involves laboratory surveillance systems and investigations conducted by epidemiologists and laboratories.

Lisa Landry - Director, Enteric Surveillance and Population Studies, Public Health Agency of Canada
We're like disease detectives. We use our surveillance system to identify those who are sick, we then confirm that those sick people are part of an outbreak, we gather information from them in order to determine cause. We collect all of the information from our investigation to give us clues as to what is causing the outbreak.

Lisa Landry - Director, Enteric Surveillance and Population Studies, Public Health Agency of Canada
We have a number of state-of-the-art systems that track reported illnesses in Canada. They tell us how many illnesses to expect in a given time period in a given area. When we see a larger number of people experiencing illness than we would expect, our epidemiologists investigate. An outbreak is identified when those sick people share something in common that could explain their illness.

Narrator
The National Enteric Surveillance Program is one of the key systems the Public Health Agency of Canada uses to identify and monitor laboratory-confirmed cases of enteric illness.

Narrator
The Public Health Agency of Canada leads the response to an outbreak when cases are reported from more than one province or territory. The Foodborne Illness Outbreak Response Protocol guides that response and sets out how the various partners work together.

Lisa Landry - Director, Enteric Surveillance and Population Studies, Public Health Agency of Canada
Solving an outbreak is like putting together the pieces of a puzzle, except we don't know how many pieces the puzzles has, we don't know what the picture looks like, we many not have all the pieces, and we don't know where to find them.

Lisa Landry - Director, Enteric Surveillance and Population Studies, Public Health Agency of Canada
We start by asking patients questions, using simple questionnaires to find out where they were, what they ate, and what they did in the days before their illness started.

Lisa Landry - Director, Enteric Surveillance and Population Studies, Public Health Agency of Canada
The interview data are analyzed using various statistical methods. Food testing also provides us with important information about whether or not a common food is the source of illness… however if the food has a short shelf life, like fresh produce, there may be none left to test, and that adds to the challenge of trying to identify the source of the outbreak.

Narrator
When the confirmed source of an outbreak is a food, and that food is still available, it is recalled from store shelves.

Narrator
Epidemiological data can be inconclusive due to poor food history recollection or lack of contaminated product to test. That’s why, in many cases, a source of an outbreak is not identified.

Narrator
Epidemiological investigations are essential for responding to food-borne illness outbreaks. They also play a key role in preventing food borne diseases. Investigations may find new pathogens, new food vehicles, and unsuspected gaps in the food safety system.

Narrator
For more information and updates, please visit our website at www.foodsafety.gc.ca

Narrator
A message from the Government of Canada.

Disease Detectives at Work

Epidemiologists are “disease detectives.” They work to find out the “who, what, where, when and why” of diseases, including foodborne diseases, and then use that research to control health problems.

The Public Health Agency of Canada works with provinces and territories to watch for a rise in cases of foodborne illness above regular levels. If a larger number of people than expected appear to have the same illness in a given period and area, it’s called a cluster. When an investigation shows that ill persons in a cluster have something in common to explain why they all got the same illness, the group of illnesses is called an outbreak.

The Public Health Agency of Canada has epidemiologists on staff who investigate outbreaks of foodborne illness when they occur in more than one province, territory or country. We also provide epidemiological support to provinces and territories upon request.

The Public Health Agency of Canada plays a leadership role in coordinating the response to national food-borne illness outbreaks, which are outbreaks that occur in more than one province, territory, or country (including Canada). The investigation of, and response to, national outbreaks in Canada may involve several organizations at multiple levels of government with complementary responsibilities. The Foodborne Illness Outbreak Response Protocol guides the coordination of roles and responsibilities during such an outbreak.

More food safety information

Visit the Government of Canada food safety portalto stay on top of food safety.

Health Canada has food safety information aimed at specific groups that are at greater risk for serious illness, including a chart that lists foods to avoid and safer alternatives to those foods.

Canadian Partnership for Consumer Food Safety Education provides information about food safety in the home.

Action on Weatherill Report Recommendations to Strengthen the Food Safety System: Final Report to Canadians describes changes made to the food safety system since 2008.

These links provide more detailed information about the tools we use to help us in our food safety work.

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