The study surveyed over 100 spa pools in 88 locations, with 23 spa pools found to contain legionella bacteria. Sixteen of these had passed current accepted levels for routine microbiological parameters.

Speaking at the agency's annual conference, Dr. Susanne Surman-Lee, who led the research, said, "In every spa pool related outbreak that we have investigated, the pool had not been managed or designed according to guidelines or had poorly trained staff. In addition, at present, testing for legionella is not mandatory for spa pools.

"Because spa pools are increasing in popularity, we need greater recognition and understanding of the risks associated with their use and misuse. They have the potential to cause infection because the water systems become contaminated with bacteria and the high temperatures of the water make considerable demands upon the disinfection and filtration systems, making it easy for the bacteria to develop and spread if not adequately maintained. The jets from spa pools then produce aerosols containing legionella which can then be inhaled and cause illness."

During 2003, there were 27 cases of Legionnaires' disease in England where spa pools were identified as the source of infection, with three deaths.

Publication date: 09/27/2004