News and Notices

Five people hospitalised with Legionnaires’ disease in November

Posted 3 years ago

Gardeners are being warned to protect themselves against Legionnaire’s disease after five people were hospitalised with the disease in November alone.

Of the five cases:

  • four were in the Tasman district and one in Marlborough
  • one patient was in their fifties, three in their seventies and one in their eighties
  • four were men and one a woman
  • in four cases the species of bacteria was Legionella longbeachae, and in one case Legionella pneumophila
  • all patients had recently purchased and used potting mix, compost or both
  • average length of hospital admission 11 days
  • range of stay in hospital 5 to 21 days

10 cases in total have been confirmed in 2020 to date, compared to eight in 2019. There have been 71 cases in the region since 2010.

Dr Stephen Bridgman, Clinical Director of Public Health and a Medical Officer of Health for Nelson Marlborough Health, says that Legionnaires’ disease is a serious, but preventable illness.

“The length of hospital stay among cases this year indicates just how serious this disease can be. It can cause pneumonia and, in some cases, death,” Dr Bridgman says.

“Fortunately we have had no deaths locally in the last three years, but sadly there was a death in Dunedin last year.”

Potting mix is the most common source of the Legionella bacteria; it’s also present in compost, inadequately-treated spa pools and hot water cylinders that are not set to a minimum of 60 degrees Celsius. 

People at greater risk of severe illness from Legionnaire’s disease are those who:

  • are over 50 years of age
  • smoke, or have chronic illnesses that suppress their immunity
  • do not take the recommended preventative steps when using potting mix or compost

“The true number of Legionella infections is highly likely to be an underestimate as the tests are usually only done if someone is sick enough to be admitted to hospital, and the bacteria are very common in potting mix and compost. Less severe cases can have an illness resembling flu or COVID-19, which is called Pontiac Fever. Unlike flu or COVID-19 the disease cannot be transmitted from person to person. Instead, people can catch it by inhaling soil or compost dust as the legionella bacteria are commonly found in the environment,” Dr Bridgman says.

“Recent cases in our region have all been connected to soil, compost or potting mix while gardening without using adequate protection. At this time of year, when people are getting into their gardens more we urge people to take care when handling these products, and to follow advice to reduce their risk, in particular the use of masks to prevent inhaling the bacteria when handling potting mix or compost,” Dr Bridgman says.

“The Legionella bacteria also lives in warm water, so people who have spa pools need to properly treat their water and maintain their pools. Maintenance of hot water cylinders, keeping cylinder temperatures at a minimum of 60 degrees Celsius and the maintenance of cooling towers are also very important.”

5 simple steps to avoid Legionnaires’ disease when gardening:

  1. Open potting mix bags carefully using scissors, rather than by ripping them
  2. Wear a face mask and gloves, and open the bag away from your face
  3. Do your potting in a well-ventilated area outdoors
  4. Dampen down the potting mix or compost with a sprinkle of water to reduce airborne dust
  5. Wash your hands thoroughly after handling potting mix, or gardening.

Symptoms of Legionnaires’ disease include:
Early symptoms can appear 2-14 days after exposure and are similar to the flu:

  • fever and chills
  • flu-like symptoms and cough
  • shortness of breath
  • muscle aches, headaches and stomach pain
  • vomiting and diarrhoea.

Anyone with these symptoms should seek health advice straight away by contacting their GP or Healthline, and let them know you have been handling potting mix, soil or compost recently. Early treatment is effective.

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