Learn More About Contamination of Potable Water Systems and the Consequences
| Report | Conclusions/Consequences |
| 37 clusters of Legionnaires’ disease identified in French tourist accommodation (27 hotels and 10 campsites). Water samples taken from 35 sites, 16 of which had Legionella pneumophila levels greater than 103 CFU/L.1 | Control measures were implemented - this included the immediate closure of 6 hotels. |
| Legionella spp. colonisation of hot water in 40 hotels in 5 Italian towns. 60% of the water samples were positive, 87% of the isolated species were Legionella pneumophila.2 | “…Italian hotels, particularly those located in old buildings, represent a major source of risk for Legionnaires’ disease due to the high frequency of Legionella contamination…” |
| An outbreak detection programme in the Netherlands exposed Legionella spp. sources including showerheads in a house, mobile home, sauna and a camp site.3 | Systematic sampling and cluster recognition can contribute to outbreak detection and lead to cost effective prevention of Legionnaires’ disease. |
| 828 residents in French retirement homes were assessed over a 4 month period. 32 Pontiac-like episodes were recorded, whilst an audit of the hot water systems identified Legionella spp. in the water and shower aerosols.4 | Legionella spp. in water and shower aerosols associated with Pontiac fever were identified. Immunosuppressive therapy can significantly enhance susceptibility to Legionella bacteria. |
| Cases of travel-associated Legionnaires' disease in Thailand were identified. Tests conducted on water in 4 suspected hotels revealed 24% (38/155) of samples were positive for Legionella spp.5 | The authors recommend a Legionella control programme for hotels that should be linked to renewal of their annual operating licence. |
| 14/21 Greek ferries were Legionella-positive (37.8% of the hot water samples and 17.5% of the cold water samples).6 | Water distribution systems of ferries can be heavily colonised by Legionella spp. presenting risk for passengers and crew members. |
| Two workers contracted Legionnaires' disease at a UK meat processing firm. The source of the contamination was a jet washer used for cleaning.7 | The plant was shut down to allow initial investigations and the firm fined £25,000 with £20,000 costs for failing to protect workers. |
| A hotel in Orlando, Florida was closed after 4 guests contracted Legionnaires’ disease.8 | The hotel was shut for 2 weeks during the investigations. |
| A water treatment company, conducting risk assessments within several UK nursing homes, was prosecuted following routine checks revealing inadequate controls for Legionella.9 | The company was fined £41,000 for placing the elderly residents at risk. |
| Following the discovery of Legionella in showers a swimming complex, the complex (which has 500,000 visitors per year) was closed.10 | The complex was closed for 18 days. |
| Two people contracted Legionnaires' disease in a newly built block of flats in Copenhagen. Patients tested positive for Legionella pneumophila serogroup 1, the same strain as identified in the hot water supply.11 | The hot water was heat treated to 70 ºC for 12 hours initially, and then treated again to 70 ºC for 24 hours plus hyperchlorination. Only the second intervention had sufficient effect on the Legionella colonization. |
| Two visitors to a Scottish leisure resort contracted Legionnaires' disease and one died. Samples from the hot tub and two shower heads were found to be positive for Legionella spp.12 | The owners of the leisure complex pleaded guilty to a lack of suitable risk assessments and a safe system for managing and controlling the risks from Legionella. They were fined £120,000. |
| 92 water samples were collected from public transport vehicles within the Piedmont region of Italy. Analysis by PCR revealed the following percentage positive water samples: Trains 78%; Planes 44%; Buses 100%; Ferries 100%.13 | Further investigation to establish the association between exposure during travel on public transport and Legionnaires' disease is being carried out. |
- Decludt et al. Eurosurveillance (2004); 9: pii=446
- Borella et al. Appl. Environ. Microbiol. (2005) 71: 5805-13
- Den Boer et al. Int. J. Hyq. Environ. Health (2007) 210: 1-7
- Bauer et al. J. Epidemiol. Community Health (2008) 62: 913-20
- Buathong et al. LEGIONELLA 2009, Institut Pasteur, Paris France October 13-19, 2009 (Poster P134)
- Goutziana et al. BMC Public Health (2008) 8: 390
- Lancashire Evening Post 27 July 2009
- The Star (Sheffield) 3 August 2009
- The Western Mail 7 August 2009
- Nottingham Evening Post 22 October 2009 and www.mansfield.gov.uk
- Krøjgaard et al. Eurosurveillance (2011); 16: pii=19759
- http://www.dailyrecord.co.uk/news/health-news/2011/03126
- Miglietta et al. 26th Meeting of the European Working Group for Legionella Infections, 25-27 May 2011, Vienna, Austria. Abstract Book, P63