Epidemiological information: Outbreak of E. coli infections linked to romaine lettuce

December 28, 2017

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 below forms 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. Number of people infected with E. coli O157Figure 1 footnote *
Figure 1
Figure 1 footnote *

Dates available for 42 cases.

Return to Figure 1 footnote * referrer

Figure 1. Number of people infected with E. coli O157 - Text description
Number of people infected with E. coli O157Figure 1 table footnote *
Week of symptom onset or specimen collection Number of cases
15-Nov-2017 0
16-Nov-2017 1
17-Nov-2017 2
18-Nov-2017 6
19-Nov-2017 2
20-Nov-2017 3
21-Nov-2017 4
22-Nov-2017 4
23-Nov-2017 1
24-Nov-2017 1
25-Nov-2017 1
26-Nov-2017 1
27-Nov-2017 3
28-Nov-2017 3
29-Nov-2017 2
30-Nov-2017 0
1-Dec-2017 0
2-Dec-2017 1
3-Dec-2017 2
4-Dec-2017 1
5-Dec-2017 1
6-Dec-2017 1
7-Dec-2017 1
8-Dec-2017 0
9-Dec-2017 0
10-Dec-2017 0
11-Dec-2017 0
12-Dec-2017 1
13-Dec-2017 0

Note: It can take several weeks from the time a person becomes ill to when this illness is reported and testing confirms a link to the outbreak.

Figure 1 table note *

Dates available for 42 cases.

Return to figure 1 table note * referrer

Table 1: At a Glance
Outbreak status Ongoing
Case count 42
Visitors to Canada 0
Provinces/Territories 5
Hospitalizations 17
Deaths 1
Gender (m:f) 11 : 31
Age range in years 3-85
Recall No
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