Take care with compost Legionnaires rising alarmingly

Friday November 21, 2014

Just as the weather improves and more of us are taking to our gardens, there has been a surge in the number of cases of Legionnaires' disease (Legionella) at Christchurch Hospital.

There have been 11 cases during October and November, nine of whom confirmed they had recently been gardening or were exposed to compost or potting mix – most did not realise the risk from working with potting mix and compost.

Legionella is a bacterium commonly found in soil and organics soil improvers such as potting mix or compost. It thrives in warm, moist conditions and becomes dangerous when dust or droplets from one of these products infected with Legionella bacteria is inhaled. It can then cause a severe, even fatal disease.

Christchurch Hospital admitted ten cases of legionella pneumonia and at least one of these required treatment in intensive care.  Canterbury Medical Officer of Health Dr Alistair Humphrey wished to warn people ahead of what could be a busy, and potentially risky weekend in the garden.

"It is important gardeners follow five simple steps to avoid catching Legionnaires' disease from potting mix or compost," says Dr Humphrey. The five steps are:

  • Open potting mix bags carefully using scissors, rather than by ripping them

  • Wear a disposable face mask and gloves, and open the bag away from your face

  • Do your potting in a well-ventilated area outdoors

  • Dampen down the potting mix or compost with a sprinkle of water to reduce airborne dust

  • Wash your hands thoroughly after handling potting mix, or gardening.

Anyone can catch Legionnaire's but certain people are more vulnerable including people over 50 years of age, those with a long-term illness, particularly lung disease, people with low immunity, and smokers. Symptoms include dry coughing, high fever, chills, diarrhoea, shortness of breath, chest pains, headaches, excessive sweating, nausea, vomiting and abdominal pain. Anyone who gets these symptoms should see their general practice right away, and let them know they have been handling potting mix or compost recently.

"Gardening is a great way to improve your physical and mental health, but please, do it safely – simply following the five steps will help protect you from a very nasty illness indeed.

You can get more information on safe gardening by visiting this website:

https://www.healthed.govt.nz/resource/safer-and-healthier-gardening
and on Legionnaires' disease by visiting these websites:

http://www.health.govt.nz/publication/communicable-disease-control-manual-2012
http://www.dbh.govt.nz/bomd-legionellosis  

ENDS​

Page last reviewed: 25 November 2014
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