Take precautions with compost and potting mix
17 November 2015
Take precautions
with compost and potting mix
It is spring, so Aucklanders are outdoors preparing the garden for summer, or tending to the veggie patch. Medical Officer of Health Dr Simon Baker enjoys gardening as much as the next person, but he’s urging gardeners to take care with composts, potting mixes, and similar products.
“Composts and potting mixes are great for boosting plant growth, but they can also be fertile ground for one of the bugs that cause Legionnaire’s disease,” he says.
“Legionnaires’ disease is a serious illness, causing pneumonia, and usually requires hospital treatment. It has caused deaths in New Zealand that have been directly linked to potting mixes and composts,” Dr Baker says.
New Zealand has one of the highest
incidences of Legionnaires’ disease in the world. This is
probably because one of the rarer forms of the bacteria
internationally, Legionella longbeachae, is the predominant
species in New Zealand. This is the species most often found
in potting mixes and composts.
In the last six months,
14 of the 37 cases of Legionnaire’s disease in the
Auckland region were L. longbeachae cases. Auckland has had
sixlongbeachae cases notified in the last two weeks, typical
for this time of year.
The Canterbury region has the country’s highest incidence of Legionnaires’ disease. Fatalities in that region have prompted medical practitioners to assume Legionnaires’ disease is the cause of pneumonia in gardeners, until proven otherwise.
The legionella bacteria is contracted simply by breathing it in. Dr Baker advises gardeners take a sensible approach to avoid inhaling dust from potting mixes and composts. Gardeners can reduce the risk with a few simple precautions.
• Minimise the amount of dust generated when working in the garden
• Do your potting in a well-ventilated
area, or outdoors, as you can breathe in Legionnaire’s
disease bacteria
• Open compost bags carefully
using scissors, rather than ripping them open
•
When opening a compost bag, keep your head and face well
clear. Open the bag slowly, and away from your face.
•
Moisten dry compost before use. Dampen down dry compost
heaps before turning or use.
• Water your plants
using a gentle spray
• Avoid hand-to-mouth
contact while gardening
• Wear gloves when
handling compost. Thin latex (or latex-free for allergy
sufferers) gloves can be worn for delicate work.
•
Fold over and clip (e.g. with a clothes peg) the top of
compost bags when not in use
• Avoid storing
compost in greenhouses, as these will heat up, and may
encourage Legionella bacteria to grow. Store bagged compost
in a cool, dry place.
• Consider wearing a P2
dust mask when turning compost heaps and handling composts
and potting mixes. These cost about $10 for a pack of three
from hardware stores, but should be thrown away after a day
in the garden.
• Finally, and most important of
all, wash your hands thoroughly after handling compost or
doing any gardening, even if you were wearing
gloves
Anyone can catch Legionnaires’ disease but the
most vulnerable are those over 50, those with a long-term
illness, lung disease, low immunity or cigarette
smokers.
Symptoms of the disease include:
•
coughing
• high fever
• shortness of
breath
• chest pains
“This is a lovely time of the year, but look after yourself in the garden,” Dr Baker says. “If you are unlucky enough to catch pneumonia, tell the doctor if you have worked in the garden in the last two weeks.”
Ends