Toi Te Ora - Public health Service have issued a warning about a disease contracted by potting mix.

Compost, potting mix and garden soils often contain the bacteria which cause legionellosis - also known as Legionnaires' disease. Infection can occur when dust from compost and potting mixes is inhaled.

Legionnaires' disease can vary in severity from a flu-like illness to severe pneumonia. Symptoms include fever, chills, muscle aches and pains, shortness of breath and coughing.

Anyone who develops such symptoms within 2 - 10 days after handling compost or potting mix should see their doctor without delay. It can be a serious illness that requires hospital treatment.


The disease is more common in middle-aged and older people, smokers, people with underlying lung disease and other long term conditions such as diabetes, and those with weaker immune systems.

Young, fit and healthy people are less commonly affected. The disease does not spread from person to person.

Gardeners and farmers can take simple steps to reduce the risk of getting Legionnaires' disease, says Dr Neil de Wet, Medical Officer of Health.

"When working with compost and potting mix it's important to take measures to avoid inhaling dust. For example, open potting mix and compost bags gently and away from your face, cut the bag open with scissors rather than ripping it, water gardens gently using low pressure, and avoid working in unventilated places such as closed sheds and greenhouses," he says.

"When potting plants, gently wet the soil or compost first to reduce dust, and wash your hands after handling soil or compost. Use of a face mask is recommended especially when these other measures are not practical or possible."

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