Legionnaires' disease and Pontiac fever after using a private outdoor whirlpool spa.

Pontiac fever and Legionnaires' disease are regarded as clinically and epidemiologically distinct diseases, caused by bacteria of the genus Legionella. Although several outbreaks of either Pontiac fever or Legionnaires' disease have been reported, they are rarely seen simultaneously. In this report we describe such a simultaneous outbreak of Pontiac fever and Legionnaires' disease that occurred in the Netherlands. In August 2009, 1 patient with Legionnaires' disease and 3 patients with Pontiac fever, all from a single family, were reported to the Municipal Health Service. All family members had been exposed to the private whirlpool spa in the garden of their home. A sampling investigation by the Legionella Source Identification Unit (LSIU) showed that a sample from the whirlpool spa, as well as a sample from the garden shower and 2 samples from a garden hose were positive for Legionella pneumophila serogroup 1, and genotyping results indicated the AFLP-type 004 Lyon (ST47) to be present in these samples.