In 1976, people attending an American Legion convention contracted an unidentified disease, later traced to bacteria in a hotel air-conditioning unit. The potentially fatal disease, known as Legionnaires disease since that first outbreak, is still most commonly associated with air-conditioning units.
So what has Legionnaire's disease to do with the potting shed? In recent years the legionella bacteria that cause the disease have also turned up in soil and commercial potting mixes, a potential hazard to nursery employees and home gardeners alike.
Millions of bags of potting mix are sold each year, and while there are relatively few cases of Legionnaire's contracted this way, it's important to remember that the disease could be fatal. If you use a potting or soil mix, you should take precautions to prevent inhaling or ingesting dust or particles.
Legionnaire's disease is not passed on from person to person, so there is no danger from contact with someone who has the disease.
While legionnaire's disease can affect anyone, doctors say it is particularly dangerous to people who are elderly or ill, or people with poor immune systems.
Sufferers have described the first signs of the disease as similar to having a cold or the 'flu. Symptoms can include:
sudden high temperature
severe headache
muscular aches
rash
stomach cramps and diarrhoea
dry cough
pneumonia
shortness of breath
Legionnaire's disease is a serious condition. If you experience severe symptoms like these after working with potting mix or soil, you should seek medical advice.
Jeff Green, a keen gardener, whose passion for potting led to a near-fatal encounter with Legionnaire's disease.
Jeff described his illness as a real shock "I've always been a healthy bloke. I thought at first that I had the 'flu, but then it got a thousand times worse. I had a rash, a painful headache, abdominal pain, and dangerously high temperature. "
As his condition worsened, Jeff was admitted to intensive care. "I don't remember much about that, but my wife thought I was going to die."
Released after two weeks in hospital, it took months for Jeff to recover. "I was one of the lucky one's - I'd been fit to start with. Some sufferers develop with kidney failure and collapsed lungs. Some don't survive."
Jeff is now concerned that while Legionnaire's disease is a high-profile disease, most reports concentrate on air-conditioning units, and not enough gardeners are aware of the dangers.
"Ultimately", Jeff says," your health is in your own hands. I'm back in the garden now, but I always take the proper precautions when handling potting mix."
The potting mix he used did have a general warning, "but it was hidden in the small print. It didn't mention legionnella, or recommend use of a mask. "
While he doesn't think gardeners should stop using potting mix, he wants to warn others about the danger, and believes that all bags of soil and potting mix should carry prominent safety warnings.
After his brush with the deadly disease, Jeff did a bit of research. Here are his tips for safe gardening:
wear gloves
wear a mask when opening bags or using the mix
wash your hands after gardening
don't leave bags in the sun, or in a hot car
perforate bags to reduce pressure caused by heat
hose material down gently to settle any dust
avoid handling the mix while smoking, or if you are breathing heavily from strenuous activity.
avoid disturbing dust when handling dried-out pot plants - water down first.
