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

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.

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.

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

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

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

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

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

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

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

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.

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

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

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

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

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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.