Legionnaires’ disease is typically acquired through inhaling a fine mist or water vapor through poorly maintained water systems. The disease can be spread through showers, cooling towers, and hot tubs; however, there are also two rarer modes of infection – decorative water fountains and potting mix.
Although much less likely, it is possible that a fountain without obvious aerosol-generating capability to be the source of a Legionnaires’ disease outbreak. In 2005, Rapid City, South Dakota experienced an outbreak of Legionnaires’ disease in which 13 individuals reported acquired the disease from June to November 2005. It was eventually discovered that a decorative fountain located in a restaurant was the culprit.
Contracting Legionnaires’ disease can also occur from non-water sources such as compost and potting mix. Legionella longbeachae is a strain of Legionella originally isolated from a patient with pneumonia in Long Beach, California in 1980. It has also been seen in Australia, New Zealand, Japan, and Scotland.
According to the CDC, while Legionella pneumophila is typically found in aquatic environments, L. longbeachae is rarely isolated from water and there have been no reports of infection from water systems. The relationship between potting mix and legionellosis was established in 1989 in Australia when a cluster of L. longbeachae infections pointed to a commercial potting mix as the source of the illness.
To read more about these to methods of contracting Legionnaires’ disease, please visit http://www.legionlawjournal.com/2013/10/01/rarer-sources-of-legionella-infection/