A cluster of cases of legionnaires' disease associated with exposure to a spa pool on display.

Interviews with four apparently sporadic cases of legionnaires' disease identified by laboratory reporting in one health district revealed that three of the four cases had been exposed to a new design of spa pool on display at a retail outlet. The fourth case had been exposed to the same design of spa pool in a private home. None had bathed in the spa pool. Legionella pneumophila serogroup 1 mAB subgroup 'Philadelphia' was isolated from samples taken from both spa pools. The display pool had not been maintained as recommended for a public spa pool in use by bathers. Revised maintenance instructions were issued to all purchasers of these spa pools in the United Kingdom (UK) and overseas. Patients may not remember specific exposures; scrutiny of activity diaries helped to identify exposure to a common location. Even when not in use by bathers, spa pools on display can be a source of legionella infection and should be maintained according to current hygiene guidelines.