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 20 th July 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 1 st weekend Fri 20 Julpm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Cum. cases

Week 1... Fri 20 Jul4pm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Mon 231 st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview5 Cum. cases

...Week 1... Fri 20 Jul4pm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Mon 231 st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview5 Tue 24More cooling towers (neighbouring areas). Env sampling – epi directed: cooling towers, hot tub (JTF), water features, etc. 8 Cum. cases

...Week 1... Fri 20 Jul4pm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Mon 231 st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview5 Tue 24More cooling towers (neighbouring areas). Env sampling – epi directed. Cooling towers, hot tub, water features, etc. 8 Wed 252 nd OCT. 5 respiratory samples identical subtype. ? Point source9 Cum. cases

...Week 1... Fri 20 Jul4pm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Mon 231 st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview5 Tue 24More cooling towers (neighbouring areas). Env sampling – epi directed. Cooling towers, hot tub, water features, etc. 8 Wed 252 nd OCT. 5 respiratory samples identical subtype. ? Point source9 Thu 261 st Health Advice Cell meeting11 Fri 273 rd OCT. Review all potential sources (registered/ unregistered)15 Cum. cases

...Week 1 Fri 20 Jul4pm: 2 cases reported to HPU. Stoke residents2 Sat & Sun7 cooling towers assessed. Shock treatment. Mon 231 st OCT. EOC. Inform GPs, hospitals, labs, NHS direct. Interview5 Tue 24More cooling towers (neighbouring areas). Env sampling – epi directed. Cooling towers, hot tub, water features, etc. 8 Wed 252 nd OCT. 5 respiratory samples identical subtype. ? Point source9 Thu 261 st Health Advice Cell meeting11 Fri 273 rd OCT. Review all potential sources (registered/ unregistered)15 Sat & Sun? Hot tub – same SBT as respiratory samples ! Re-check Cum. cases

Spa pool/hot tub - JTF - retail ‘Mega’ discount store

Week 2 Mon 30Probable source (JTF store). Media briefing. 1st death.18 Tue 31Worried well – GP queries. GP letters, NHS direct.19 Wed 1 Aug4 th OCT. All env samples negative – apart from hot tub & 1 cooling tower (different SBTs). 2 nd Health Advice Cell meeting. Thu 215 discharges from hospital. Fri 35 th OCT. No further positive env samples. LA legal proceedings. FOI requests start. 20 Sat & Sun

Week 3 and 4 Mon 6Two remaining cases in hospital. 2 nd death in hospital. Tue 7Last confirmed case detected Tue 14Last OCT Fri 17 AugDay 29. Close outbreak

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.

Epidemic curve

Onset to presentation: 3 – 7 days Source drained Source confirmed Exposure

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 JTF retail ‘Mega’ discount store 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

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

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. Spa pools (hot spa/ hot tub/ whirlpool spa, “Jacuzzi”)