1. Session 13/14: Outbreak Exercise
Facilitator notes:
Legionnaires’ disease: Risk assessment, outbreak investigation and control
Session 13/14: Outbreak Exercise
ECDC, 2012

2. Scenario
It is the afternoon of Friday 19 October, a call is received from the local hospital saying they have identified Legionnaires’ disease in two local residents. They have started appropriate antibiotic treatment but one of the cases is critically ill and has been transferred to intensive care.
Question 1a What evidence would you want in order to make a diagnosis of Legionnaires’ disease at this stage?
Question 1b What steps should be taken in response to the information you have received?
Time allowed 10 minutes and 5 minutes for feedback and discussion.

3. Information update - Friday 19/10
The hospital reports a third case and has confirmed that the cases are urinary antigen +ve. All have clinical and radiological evidence of pneumonia. One case was admitted to hospital on 13 October, one on 14 October and the other on 17 October. No case has any history of foreign or UK travel. All lived within 4 miles of each other and in an area just south of the city centre.
On looking through notification data you identify a case of Legionnaires’ disease that was notified on 26 September and another one on 30 August. On this basis it is decided to convene an outbreak control meeting to assess the situation and decide what action may be needed.
 Question 2. When would you convene the meeting and who should attend?
 Time allowed 5 minutes
 Question 3. Draw up an agenda covering the main issues to be discussed at the outbreak control meeting.
 Time allowed 10 minutes
 Question 4. What actions should be organised at this stage?
Time allowed 15 minutes
 15 minutes for feedback and discussion.

4. Information update At the meeting it was decided to
gather the information on the cases as quickly as possible,
identify the cooling towers in the south of the city,
sample them and arrange for them to be shock treated.
Is there anything else you would want to do?
Time allowed 10 minutes

5. The case on 30 August spent a significant element of their time abroad
The case on 30 August spent a significant element of their time abroad. What would your case definition be?
Time allowed 10 minutes

6. Communications
One of the actions from the meeting is to prepare a reactive press release. You have 20 minutes to list the key issues you would wish to include. Time allowed 20 minutes

7. Information update – 22 October
There are now 8 confirmed cases and 2 possible cases
A sample could only be taken from one tower but all the towers have been shock treated.
Is the geographic mapping of cases consistent with the cooling towers as the source?
What additional information might you want?
Time allowed 10 minutes

8. Information update – 23 October
Can you draw any conclusions? What actions would you now take?
Time allowed 20 minutes

9. Information update - 23 October pm
The clinicians managed to get clinical specimens from 4 of the patients. What testing would you want done?
Time allowed 5 minutes

10. Information update - 24 October am
Have you found the source?
Time allowed – 5 minutes

11. Information update - 24 October pm
L. pneumophila serogroup 1, ST 1958 is identified from all four patients. How does this affect your view on the possible source of the outbreak?
Time allowed 10 minutes.

12. Information update – 24 October
In light of the clinical and environmental findings what do you plan to do now?
Time allowed 20 minutes

13. Information update – 23 October
There are now 10 cases is any further action needed? Time allowed – 5 minutes

14. Information update - October 26 am
Swabs were taken form the spa tub on the Hatters Row premises – results below. What can you conclude from these results?
Time allowed 10 minutes

15. On re-interviewing the cases all of them visited Hatters Row within the incubation period. The epidemic curve is shown below. Have you enough information to identify the source? What pieces of information give you the confidence that you have? 1 2 3 4
15/05/2012
17/05/2012
19/05/2012
21/05/2012
23/05/2012
25/05/2012
27/05/2012
29/05/2012
31/05/2012
02/06/2012
04/06/2012
06/06/2012
08/06/2012
10/06/2012
12/06/2012
14/06/2012
16/06/2012
18/06/2012
20/06/2012
22/06/2012
24/06/2012
26/06/2012
28/06/2012
30/06/2012
02/07/2012
04/07/2012
06/07/2012
08/07/2012
10/07/2012
12/07/2012
14/07/2012
16/07/2012
18/07/2012
20/07/2012
22/07/2012
24/07/2012
26/07/2012
28/07/2012
30/07/2012
01/08/2012
Number
Date of onset of cases of Legionnaires' disease reported, by case status October 2012
Confirmed
Possible
Spa pool closed

16. What are the next steps?

17. Facilitator notes:
Acknowledgements The creation of this training material was commissioned in 2010 by ECDC to Health Protection Agency (UK) and the University of Chester (UK) with the direct involvement of Louise Brown, Janice Gidman, Emma Gilgunn-Jones, Ian Hall (on behalf of the ECDC Legionnaires Disease Outbreak Toolbox Development Group), Tim Harrison, Rob Johnston, Carol Joseph, Sandra Lai, John Lee, Falguni Naik, Nick Phin, Michelle Rivett, and Susanne Surman-Lee. The revision and update of this training material was commissioned in 2017 by ECDC to Transmissible (NL) with the direct involvement of Arnold Bosman and Kassiani Mellou.