Legionnaires Disease Health Warning

Legionnaires Disease Health Warning

New Zealand health authorities are warning gardeners to be aware that potting mix can cause a fatal disease called Legionnaires Disease if handled improperly.

The Legionnaires Disease warning comes after a coroner ruled that a Christchurch woman Margaret Valenski , who died on Boxing Day in 2011, was probably caused by Legionnaires Disease contracted after working with potting mix or compost. Canterbury medical officer of health Ramon Pink says “Enjoy your gardening by all means, but please make sure you avoid inhaling the dust from potting mix or compost as this can be dangerous.”

Legionnaires Disease is a type of pneumonia caused by bacteria. It is a potentially fatal, acute infectious respiratory process caused by any species of the aerobic bacteria belonging to the genus Legionella. It is not transmitted from one person to another person. The common transmission route for the disease is breathing in dust or water aerosols contaminated with the bacteria. Sources where temperatures allow the bacteria to thrive include cooling towers , hot-water tanks, and evaporative condensers of large air-conditioning systems, such as those commonly found in large office buildings and hotels.

The symptoms of Legionnaires Disease are a high fever, chills and a cough which may be dry or produce sputum. Some patients also have headache, muscle aches, tiredness, loss of appetite, loss of coordination (ataxia), and occasionally diarrhoea and vomiting. Impaired cognition and confusion and may also occur. So if you have these symptoms it’s best to go to see your doctor urgently.

In New Zealand in 2010 there were five related deaths and 136 hospitalisations caused by Legionnaires Disease related problems . There have been years where New Zealand has had seven or eight deaths. The death rates are normally higher if there has been no medical intervention.
The best ways to reduce the risk of infection with Legionnaires Disease for gardeners are to follow these steps when handling potting mix or compost:

  • Wear a respiratory face mask covering your mouth and nose.
  • Open potting bags gently using scissors rather than tearing them open, therefore increasing the air borne dust.
  • Work in a well ventilated outside area.
  • Dampen compost and soil with water to reduce air borne dust particles.
  • Wear gloves and thoroughly was hands after handling potting mix or doing gardening.

So anyone who has the symptoms listed above should see a GP urgently and tell them if they have been handling potting mix or compost recently.

Legionnaires Disease