Transcript Legionnaire’s Disease Stoke on Trent 2012

Legionnaire’s Disease Outbreak
(point source):
Stoke on Trent, 2012
Dr Nic Coetzee
(West Midlands North HPU)
-- on behalf of the Outbreak Control Team
December 2012
Stoke-on-Trent
Phil
Taylor
The start...
Friday 20th July 2012
• 2 cases notified – lab UHNS:
- interviews
• 6-10 cases/ year average - Staffordshire
• Internal incident meeting
- No specific risk factors
- Enhanced case finding
- Cooling towers (LA, HSE)
Response – 29 busy days
1st
weekend
Fri 20 Jul
pm: 2 cases reported to HPU. Stoke residents
Sat & Sun
7 cooling towers assessed. Shock treatment.
Cum. cases
2
Week 1...
Cum. cases
Fri 20 Jul
4pm: 2 cases reported to HPU. Stoke residents
Sat & Sun
7 cooling towers assessed. Shock treatment.
Mon 23
1st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview
2
5
...Week 1...
Cum. cases
Fri 20 Jul
4pm: 2 cases reported to HPU. Stoke residents
2
Sat & Sun
7 cooling towers assessed. Shock treatment.
Mon 23
1st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview
5
Tue 24
More cooling towers (neighbouring areas). Env sampling – epi
directed: cooling towers, hot tub (JTF), water features, etc.
8
...Week 1...
Cum. cases
Fri 20 Jul
4pm: 2 cases reported to HPU. Stoke residents
2
Sat & Sun
7 cooling towers assessed. Shock treatment.
Mon 23
1st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview
5
Tue 24
More cooling towers (neighbouring areas). Env sampling – epi
directed. Cooling towers, hot tub, water features, etc.
8
Wed 25
2nd OCT. 5 respiratory samples identical subtype. ? Point source 9
...Week 1...
Cum. cases
Fri 20 Jul
4pm: 2 cases reported to HPU. Stoke residents
2
Sat & Sun
7 cooling towers assessed. Shock treatment.
Mon 23
1st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview
5
Tue 24
More cooling towers (neighbouring areas). Env sampling – epi
directed. Cooling towers, hot tub, water features, etc.
8
Wed 25
2nd OCT. 5 respiratory samples identical subtype. ? Point source 9
Thu 26
1st Health Advice Cell meeting
11
Fri 27
3rd OCT. Review all potential sources (registered/ unregistered)
15
...Week 1
Cum. cases
Fri 20 Jul
4pm: 2 cases reported to HPU. Stoke residents
2
Sat & Sun
7 cooling towers assessed. Shock treatment.
Mon 23
1st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview
5
Tue 24
More cooling towers (neighbouring areas). Env sampling – epi
directed. Cooling towers, hot tub, water features, etc.
8
Wed 25
2nd OCT. 5 respiratory samples identical subtype. ? Point source 9
Thu 26
1st Health Advice Cell meeting
11
Fri 27
3rd OCT. Review all potential sources (registered/ unregistered)
15
Sat & Sun
? Hot tub – same SBT as respiratory samples ! Re-check
Spa pool/hot tub JTF - retail ‘Mega’ discount store
Week 2
Mon 30
Probable source (JTF store). Media briefing. 1st death.
18
Tue 31
Worried well – GP queries. GP letters, NHS direct.
19
Wed 1 Aug
4th OCT. All env samples negative – apart from hot tub & 1
cooling tower (different SBTs). 2nd Health Advice Cell meeting.
Thu 2
15 discharges from hospital.
Fri 3
5th OCT. No further positive env samples. LA legal proceedings.
FOI requests start.
Sat & Sun
20
Week 3 and 4
Mon 6
Two remaining cases in hospital. 2nd death in hospital.
Tue 7
Last confirmed case detected
.
.
.
.
.
Tue 14
Last OCT
Fri 17 Aug
Day 29. Close outbreak
21
Microbiological Investigation
• Testing - all patients with ? pneumonia at UHNS
• Neg & pos samples == Colindale
• All 21 patients confirmed Legionella antigen sg 1 positive
by reference laboratory Colindale
- 2 were negative at local laboratory
• 11 sputum samples - 9 DNA sequence based typing
confirmed Legionella pneumophila sg1 ST1268
• Unique strain, never seen before
Case Definitions
Confirmed:
Clinical/radiological pneumonia
Lab conf acute Legionella (Antigen/Culture/PCR/Serology)
Onset from 30 June 2012
Lived or visited Stoke area in 14 days before onset.
Probable:
As above + onset date from 2 May 2012.
Epidemiological Investigation
2 HPU Nurses interviewing + re-interviewing all cases;
REU staff onsite - HPU EOC:
analyse data, direct investigation;
Remote analyses - Porton mapping/modelling team;
Health Advice Group:
Descriptive Epi
21 confirmed cases + 2 earlier possible cases re-investigated.
All cases live in or around Stoke.
SEX
Age
M
F
Mean
Total
Median
Confirmed
14
7
65.0
64
Possible
2
0
66.5
66.5
Total
16
7
21
2
23
0
01/08/2012
30/07/2012
28/07/2012
26/07/2012
24/07/2012
22/07/2012
20/07/2012
18/07/2012
16/07/2012
14/07/2012
12/07/2012
10/07/2012
08/07/2012
06/07/2012
04/07/2012
02/07/2012
30/06/2012
28/06/2012
26/06/2012
24/06/2012
22/06/2012
20/06/2012
18/06/2012
16/06/2012
14/06/2012
12/06/2012
10/06/2012
08/06/2012
06/06/2012
04/06/2012
02/06/2012
31/05/2012
29/05/2012
Confirmed
27/05/2012
25/05/2012
23/05/2012
21/05/2012
19/05/2012
17/05/2012
15/05/2012
Number
Epidemic curve
Date of onset of cases of Legionnaires' disease reported, by case status, Stoke-on-Trent, May-Aug
2012
4
Possible
3
2
1
Source drained
Exposure
Onset to presentation: 3 – 7 days
Source
confirmed
Is source a registered cooling
tower?
7 cooling towers – Stoke; 5 in neighbouring areas; total
8 sampled
Stoke cooling towers inspected - HSE/LA when 2 cases
reported on weekend of 21-22/7;
Inspected & sampled 23-24/7: most already treated;
Case histories - “epi fit” - analysed
nearest postcode from home, work or place visited
Only one tower positive for Legionella:
different strain to cases and poor fit epidemiologically.
An unregistered exterior source where?
 south Stoke - highest
risk for external source
from home + work
postcodes + prevailing
winds.
 >30 sites identified and
risk assessed by
LA/HSE.
 5 sites inspected +
sampled (4 negative).
Interviews, re-interviews:
sites visited by confirmed cases
All 21 visited JTF Mega discount warehouse;
14 visited The Range retail outlet;
10 visited Tesco Longton;
3 visited Morrisons Festival park;
No other site visited more than twice;
3 car washes + 3 hospitals visited by 1 case each.
Sites for further investigation
JTF, The Range, Aggregate industry, Powder coating ,
Tesco Longton all identified - visited.
•JTF - spa bath on open display
•The Range - indoor fountains: made safe and sampled.
Legionella pneumophila sg1 ST1268 found by PCR in 9
cases & sample - spa bath at JTF.
Dates of visit obtained for 20 cases:
incubation period range 3-14 days, median of 5 days.
Environmental Investigation summary
• >30 potential sites plus 12 registered cooling towers
• 15 sites higher risk, investigated and sampled
- Rob Johnston (F,W,E lab) with LA or HSE colleague
- Labour intensive
• JTF swab sample positive for Legionella pneumophila sg1
ST1268 strain
• Second site (cooling tower) positive culture Legionella
pneumophila SG1 but ST62 strain
• All other sites negative
JTF hot tub - most
probable source
Identical unique strain – cases &
hot tub, - only env source
All confirmed cases visited JTF only
Incubation periods - consistent
Spa baths - indoor display known source
Spa bath close to the tills/exit, all visitors passed nearby
JTF retail ‘Mega’ discount store
Lessons Learnt ...
• Descriptive epi
– interviews, re-interviews....
• Case finding – clinical microbiologist, GP
• Respiratory samples
• Water samples – rapid, expert, independent
• Real-time dedicated epi support – line list and
mapping
• Health advice group
• Genotyping : DNA sequence based typing
... Lessons learnt
• Command & control:
Incident director
Clinical, environ investigation & OCT chair
Media and sitrep – talking head
GP liaison and acute desk support
Epi team on-site EOC
•
•
•
•
EOC, IT
Resilience, operational demand
Media pressure, MPs ....
Safety – indoor spa pools –
public spaces
Spa pools
(hot spa/ hot tub/ whirlpool spa, “Jacuzzi”)
•Not swimming – sitting / lying
•Self-contained body of water filtered & chemically disinfected.
•Not drained, cleaned, or refilled
after each user
•Water heated to 30 – 40 deg C
•Hydrotherapy jet circulation +/- air
induction bubbles.