Legionella and garden soils

Commercial garden soils which include packaged potting mixes and bulk soil supplies have been associated with several cases of Legionnaires’ Disease in WA, as a result of exposure to the bacteria Legionella longbeachae.

How Legionella longbeachae are spread is uncertain, but it is thought that they are breathed in or spread from hand to mouth. The bacteria can remain on hands contaminated by handling potting mix and other garden soils.

Garden soils include:

• potting mixes
• gardening soils
• mulches
• composts and
• soil conditioners.

Public health management

Currently, no strategies are available to control or eliminate Legionella longbeachae growing in commercial garden soils. Soil in the natural environment may still present a risk when people are working in their gardens.

This public health risk is currently managed using the The Guideline for commercial garden soils (PDF 1MB), published under the Public Health Act 2016.

The Guideline provides information and guidance on best industry practice for managing the public health risks associated with commercial garden soils. The general public health duty, specified in Part 3 of the Public Health Act 2016, requires that all persons and businesses “must take all reasonable and practicable steps to prevent or minimise any harm to public health that might foreseeably result from anything done or omitted to be done by the person”.

The Guideline may be used to clarify the application of the general public health duty and provide information on the “reasonable and practicable steps” that should be taken to prevent or minimise harm to public health.

Safety precautions

Preventative strategies for this disease are limited to educating the community on the safe use of garden soils, which includes publishing health warnings on bagged materials and providing signage near bulked products. Such warnings attempt to inform the consumer to take precautionary measures when handling garden soils.

These recommendations include:

• using a face mask
• wearing gloves
• avoiding inhalation of dust and aerosols and
• washing hands after using the material.

Resources

• Simple steps to avoid Legionnairees – poster (PDF 3MB).