Legionellosis fact sheet

What is Legionellosis (Legionnaires' disease)?

Legionellosis, also known as Legionnaires' disease, is caused by an infection with Legionella bacteria.

Many different species of Legionella are commonly found in the environment, some of which are known to cause illness in people. In Tasmania, Legionellosis is mainly caused by Legionella pneumophila and Legionella longbeachae.

Legionella pneumophila bacteria are commonly found in water and have been isolated from hot water systems, air-conditioning cooling towers, water fountains, spa pools, hot and cold water taps and showers. These systems must be maintained according to national guidelines which reduce the risk of growing and releasing Legionella into the surrounding environment.

Legionella longbeachae can be found in potting mixes, garden soil, compost heaps and composted animal manures.

Legionellosis is a notifiable disease.

What are the symptoms?

Symptoms of legionellosis usually start five to six days after exposure to the bacteria. However, this can range between two to 10 days. 

Symptoms of legionellosis can include fever, chills, headache, muscle aches and pains, cough and breathlessness. Legionella bacteria generally infect the lung (pneumonia) which often results in severe illness. If you have these symptoms, see your doctor.

Who is at risk?

Anyone can get Legionellosis. However, older people, smokers, those with chronic lung disease and men are most commonly affected.

How is it diagnosed?

An assessment by a medical practitioner is needed to diagnose Legionellosis. Blood tests taken three to six weeks apart, urine or sputum (mucus that is coughed up) tests, and X-rays are involved in the diagnosis of Legionellosis.

How is it prevented?

The risk of Legionellosis can be reduced by ensuring the growth of bacteria in systems such as spas, hot water systems and cooling towers is controlled. There are regulations and guidelines that set out how to maintain and treat cooling towers, warm water systems and public spas to prevent Legionella bacteria growing.

People can also take care to avoid exposure to the bacteria from other sources, such as potting mix and water sources in the home. 

Person-to-person spread does not occur. Exclusion from work is not necessary.

Legionellosis most commonly occurs in the warmer months.

Taking care in the garden

Legionellosis has been linked to the use of potting mix.

To minimise the risk of infection when handling potting mix, gardeners should take the following precautions:

• always wear gloves and mask when handling soil, compost, or potting mix, preferably a properly fitted particulate respirator with a P1 or P2 filter
• handle potting mix in a well-ventilated area
• open bags of potting mix with care and direct the opening away from the face to avoid inhalation of airborne dust or particles
• avoid shaking the bag and keep the product close to the ground
• moisten the contents to avoid creating dust
• always wash hands thoroughly with soap and water after handling potting mix even if gloves had been worn
• avoid using water under high pressure on potting mix

These same measures should be adopted when handling other garden material such as compost and garden soil.

How is Legionellosis treated?

Antibiotic treatment may be prescribed by the treating medical practitioner. Sometimes, cases may need to be treated in hospital and may require intensive care.

What should I do if I develop symptoms?

If you develop symptoms of Legionellosis, book an appointment to see your General Practitioner as soon as possible.

If you have severe symptoms such as difficulty breathing or chest pain, or in an emergency, call ‘000’ for an ambulance or present yourself to the emergency department of your nearest hospital.

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