Legionnaires' disease threat to gardeners

Health warnings may be put on bags of garden compost after a pensioner caught Legionnaires' disease while gardening.

The "previously fit and healthy" 67-year-old man was admitted to the Alexandra Hospital in Paisley after suffering from fever, confusion and shortness of breath for eight days, according to a report in the Lancet medical journal.

Despite being treated with antibiotics, the man ended up in intensive care. Viral pneumonia was suspected, but doctors had difficulty diagnosing the disease. A range of tests, including a urine test for the bacterium Legionella all came back negative.

However, a sputum sample obtained through washing the man's lungs tested positive for the bacterium Legionella longbeachae, a rare type of legionella which cannot be detected in urine.

Dr Simon Patten, an intensive care consultant at the hospital, said: "When we questioned the patient to find out the source of this infection, we discovered that he was a keen gardener and had lacerated his left index finger two days before the onset of his symptoms, while planting with compost; we presumed that this cut was the site of entry of the organism."

Most Legionnaires' disease is caused by Legionella pneumophila in Britain. People usually develop pneumonia after breathing in contaminated water droplets from poorly maintained showers or air conditioning.

Cases of Legionella Longbeachae in the UK are rare; only nine cases have been reported since 1984. However, in Australia, New Zealand and Japan, it causes around 30 per cent of all cases of Legionnaire's disease. It can be found in garden soil, compost and animal manures.

Once treated, the patient's condition improved and he was discharged from hospital a week later.

When handling compost, the Royal Horticultural Society recommends people wear gloves, avoid opening compost bags with their head directly over it and not storing compost in greenhouses, as the higher temperatures may encourage the growth of the bacterium.

This article was published on Fri 3 September 2010