1. The aerosols released from a domestic spa pool: the potential risk to those in and around the pool BISHTA Annual Conference: 29 th September 2015 Ginny Moore PHE Porton Biosafety Investigation Unit

2. Public Health England 2Aerosols released from a domestic spa pool …..

3. PHE Porton: Biosafety Investigation Unit 3Aerosols released from a domestic spa pool Dealing with real-world practical problems

4. Contamination of tap components 4Aerosols released from a domestic spa pool Tap Component Number (%) of components from which Pseudomonas aeruginosa was recovered Tap body18 (26) Connectors0 Isolation valve 0 Thermostatic Mixer 2 (3) Solenoid5 (7) Flow straightener 41 (60)

5. Contamination of tap components 5Aerosols released from a domestic spa pool Tap Component Number (%) of components from which Pseudomonas aeruginosa was recovered Tap body18 (26) Connectors0 Isolation valve 0 Thermostatic Mixer 2 (3) Solenoid5 (7) Flow straightener 41 (60)

6. Contamination of tap components 6Aerosols released from a domestic spa pool Tap Component Number (%) of components from which Pseudomonas aeruginosa was recovered Tap body18 (26) Connectors0 Isolation valve 0 Thermostatic Mixer 2 (3) Solenoid5 (7) Flow straightener 41 (60)

7. Contamination of tap components 7Aerosols released from a domestic spa pool Tap Component Number (%) of components from which Pseudomonas aeruginosa was recovered Tap body18 (26) Connectors0 Isolation valve 0 Thermostatic Mixer 2 (3) Solenoid5 (7) Flow straightener 41 (60)

8. The Porton Experimental Tap Rig 8Aerosols released from a domestic spa pool

9. 9 From science to guidance

10. Bubble, Bubble, Soil and Trouble 10Aerosols released from a domestic spa pool July-August 2012 21 confirmed cases 3 deaths unique strain of Legionella pneumophila SG1 (ST1268) 30+ sites investigated by the HSE and the local authority outbreak strain isolated from a single site implicated a spa pool on display in DIY store

11. Spa pool ownership is increasing Lloyds Insurance Survey (2013) 1 in 10 of us own a outdoor hot tub (2.6 million) What Spa? probably closer to 300,000 British and Irish Spa and Hot Tub Association (BISHTA) sales have been averaging at >7,000 per year sales on an upward trend 11Aerosols released from a domestic spa pool

12. The trouble with spa pools They are warm favours the growth of human pathogens They can contain a high and variable organic load makes disinfectant levels difficult to maintain They bubble generation of water droplets (1 µm - 8 µm) can transport bacteria deep into respiratory tract 12Aerosols released from a domestic spa pool

13. Legionellae Gram-negative bacteria natural freshwater contaminants Legionellosis inhalation and deposition of legionella bacteria in the lung replication within macrophages (white blood cell) Legionnaires’ disease 922 confirmed cases (2012-2014) 3% of community-acquired pneumonias 13Aerosols released from a domestic spa pool

14. Spa-associated legionellosis Treated recreational water 18 of 116 outbreaks reported to the CDC caused by bacteria 10 (55.5%) of these were caused by Legionella spp All 10 were epidemiologically linked to spa pools 122 people developed legionellosis Dose-response effect increased time spent in a pool = increased likelihood of illness 14Aerosols released from a domestic spa pool

15. You don’t have to be in it to inhale it! One of the world’s largest outbreaks: 188 cases Pausing at the whirlpool spa was the most important risk factor 15Aerosols released from a domestic spa pool

16. You don’t have to be in it to inhale it! 16Aerosols released from a domestic spa pool

17. PHE Biosafety Investigation 17Aerosols released from a domestic spa pool Aims 1. To investigate the aerosols released from a domestic spa pool 2. Using a marker organism assess the potential risk to those in and around the pool should there be failures in disinfection practice

18. Natural contamination of the pool 18Aerosols released from a domestic spa pool

19. Method 19Aerosols released from a domestic spa pool aerodynamic particle sizerall-glass cyclone sampler

20. Method 20Aerosols released from a domestic spa pool

21. Method 21Aerosols released from a domestic spa pool

22. Results: Mass distribution of particles 22Aerosols released from a domestic spa pool

23. Results: Mass distribution of particles 23Aerosols released from a domestic spa pool

24. Results: Effect of sample height 24Aerosols released from a domestic spa pool

25. Results: Microbial air concentration 25Aerosols released from a domestic spa pool Levels in pool P. aeruginosa ~10 8 cfu * mean (n=27) distance above water line P. aeruginosa (cfu/m 3 )* 1 metre4 20 cm47 10 cm349

26. Exposure dose & probability of infection Inhalation rates: 9 litres/min (male); 6.7 litres/min (female) Retention rate: 50% deposition of a 5 µm range aerosol Infectivity per L. pneumophila cfu: 0.06 26Aerosols released from a domestic spa pool 15 minutes in a turbulent (bubbling) spa pool malesfemales estimated risk of exposure24 cfu18 cfu estimated risk of infection0.760.65

27. Results: Mass distribution of particles 27Aerosols released from a domestic spa pool

28. Results: Effect of sample distance 28Aerosols released from a domestic spa pool

29. Results: Effect of height and distance 29Aerosols released from a domestic spa pool

30. Results: Microbial air concentration 30Aerosols released from a domestic spa pool * mean (n=9) Distance from pool poolside25 cm50 cm75 cm1 m P. aeruginosa (cfu/m 3 )* 41519367

31. Results: Microbial air concentration 31Aerosols released from a domestic spa pool * mean (n=9) Distance from pool poolside25 cm50 cm75 cm1 m P. aeruginosa (cfu/m 3 )* 41519367

32. Conclusions The results confirm: a domestic spa pool can rapidly become contaminated potential pathogens will become aerosolised during activation of the air-injection system The study provides: direct data on the aerosolisation of bacteria from a spa pool data that will help inform quantitative microbial risk assessments and increase the robustness of the models used 32Aerosols released from a domestic spa pool

33. Conclusions assuming the level of aerosolisation of P. aeruginosa is similar to that of L. pneumophila: susceptible individuals either in or at the edge of a turbulent spa pool may be at risk of acquiring legionellosis but (under our experimental conditions) the risk of infection reduces with increasing height and distance from the pool 33Aerosols released from a domestic spa pool

34. Future work? 34Aerosols released from a domestic spa pool How does the size of the air jets and/or the power of the air-injection system influence the aerosolisation of respirable particles?

35. No guinea pigs were harmed in our study Thank you for listening Questions?