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ARCHIVED - Epidemiological information: E. coli O157:H7 illness related to the XL food safety investigation

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14 November 2012

What is epidemiology?

Epidemiology is the study of disease in a population. Epidemiologists, or “disease detectives,” use surveillance systems to identify those who are sick and confirm that the sick people are part of this event. They then gather information from the people who got sick and review the clues from all parts of the investigation that might reveal the cause of the illness event.

The figure and table below form part of the epidemiological investigation into this outbreak. An "epi curve" (Figure 1) is a valuable reference tool in any epidemiological investigation. An epi curve shows when cases begin, when they peak, and when they trail off. Certain details of the people who got sick (Table 1) also help epidemiologists as they work to solve the questions involved in foodborne illness.

Figure 1. People confirmed to be infected with the strain of E. coli O157:H7 detected in the XL food safety investigation, by date of illness onset

People confirmed to be infected with the strain of E. coli O157:H7 detected in the XL food safety investigation, by date of illness onset
Note: It can take two to three weeks from the time a person becomes ill to when this illness is reported and testing confirms a link to the outbreak.

Text equivalent for figure 1Map of overall Influenza activity level by province and territory, Canada

Table 1: At a Glance
Outbreak status Ongoing
Case count 18
Hospitalizations 6
Cases recovered or recovering 18
Cases with Hemolytic Uremic Syndrome (HUS) 0
Deaths 0
Gender (m:f) 10:8
Age range in years 5-63