A study by the Health Protection Agency (HPA) has found that many UK spa baths could be breeding grounds for Legionnaires’ disease because they are not managed or maintained properly.

The year-long study found that 23 of 88 spa pools contained legionella bacteria and 16 of these had already passed safety tests for microbiological contamination.

“In every spa pool-related outbreak we have investigated, the pool had not been managed or designed according to guidelines or had poorly trained staff,” said Dr Susanne Surman-Lee, who led the research.

At present, checks for legionella in spa pools is not mandatory. Instead, if pools pass routine microbiological checks it is assumed that the growth and spread of legionella is also under control, said Surman-Lee. “However, we discovered that the legionella bacterium may be present in high numbers in both privately-owned and public facilities even when routine microbiological and safety checks appear satisfactory,” she said.

There were 27 cases of Legionnaires’ disease in England in 2003 where spa pools were identified as the source of infection: resulting in three deaths. So far this year there has been only one case of Legionnaires’ reported to be associated with a spa pool.

The HPA has published spa pool guidelines since 1994 and a new joint document with the Health and Safety Executive is being produced which will update advice on the risks and legislation associated with spa pools.