The next time you head out to water your lawn, you might have reason to worry. According to researchers at the University of New South Wales, bacteria that cause Legionnaire’s Disease might have taken up residence in your garden hose.
In an eighteen month long study by Dr. Jacque Thomas of the School of Civil and Environmental Engineering, she watched the legionella bacteria growth within the humble hose. In the end, she was surprised by what she uncovered.
Legionnairs Disease is Caused by the Legionella Bacteria
Legionnairs disease is caused by the legionella bacteria. Typical patients include people with compromised immune systems as well as the elderly. It is an often fatal type of pneumonia and is passed when droplets of water containing the bacteria are inhaled.
Legionnaire’s outbreaks are linked to locations that are warm and damp, conditions that allow the bacteria to thrive. Pools, spas, and fountains have been affected. They’ll even colonize air conditioning equipment due to copious amounts of condensation. Both Brazil and the Netherlands have linked cases of Legionnaires to hose usage.
The study, published in the Environmental Science and Technology journal, noted that when garden hoses lie for long periods of time in the warm summer, they create optimal conditions for legionella bacteria. There life cycle requires that they be hosted within amoeba that proliferate within this warm and wet environment. The net result is a virulent disease.
Heat of Summer Creates Microbial Soup
The legionella bacteria is able to proliferate even when disinfection measures are taken when they are within their host. It is the warm heat of summer that creates this microbial soup.
Thomas was surprised by the concentration of both legionella bacteria and amoebas within the garden hose. The unexpected results were obtained at the UNSW Water Research Centre.
This microbial slime that supports the life cycle of legionella is referred to as biofilm. It’s literally constructed of microorganisms that line the walls of the hose. Once the water is turned on, it is dislodged and is propelled outward.
In a scientific model, Thomas showed how the air combined with water creates a pattern similar to outbreaks of Legionnaires in public spas.
Legionella proliferate at temperatures between 25 and 42 degrees. At this temperature, the amoebas turn on genes that make the bacteria increasingly pathogenic. Without the heat, this change does not occur.
Sources of Transmission of Legionnaires Disease
Although the study was small (Thomas only included two hoses), she states that it a another part of a steadily increasing body of information that suggests that garden hoses have to potential to because sources of transmission of Legionnaire’s Disease. She recommends that further studies be done.
The study is also offers insight into the growth and transmission of other species of bacteria including the parachlamydiae, mycobacterium, and pseudomonas.
In addition, more studies of the potential health implications of the simple garden hose are warranted.
There are ways to eliminate risk while waiting for more information.
Since bacteria require water to grow, it’s important to drain the hose after each use and hang it so excess water drips out. This step eliminates a potential environment for pathogenic bacteria to grow.