What you need to know about Legionnaires’ disease

Following the recent outbreak in Melbourne, we delve into the facts on Legionnaires’ disease and how to protect yourself and your family.

Since the start of the recent outbreak of Legionnaires’ disease in Melbourne, more than 70 cases have been confirmed, and two people have died.

It has prompted authorities to issue a health warning, highlighting the need for increased awareness and adherence to preventive measures to help stem the spread.

Victoria’s acting chief health officer Dr Evelyn Wong says people who live in, work in or have visited metropolitan Melbourne and surrounding areas, and who develop symptoms of Legionnaires’ disease, should seek urgent medical care.

“Legionnaires’ disease usually presents as a chest infection with symptoms such as fever, chills, cough, headache and muscle aches and pains,” Dr Wong says.

Understanding the risk factors, symptoms and preventive measures can help protect you, your family and your community.

On this page:

• What is Legionnaires’ disease?
• Symptoms of Legionnaires’ disease
• How is Legionnaires’ disease spread?
• Who is at risk of getting it?
• How common is Legionnaires’ disease?
• Diagnosis and treatment
• Is Legionnaires’ disease contagious?
• Can Legionnaires’ disease be fatal?
• What should you do if you suspect Legionnaires’ disease?
• How long does it take to fully recover?
• Can Legionnaires’ disease recur?
• Is there a vaccine for Legionnaires’ disease?
• How to prevent Legionnaires’ disease at home

What is Legionnaires’ disease?

Legionnaires’ disease, a severe form of pneumonia, is caused by Legionella bacteria.

Australian National University associate professor of medicine Sanjaya Senanayake, who is a specialist in infectious diseases, says the bacteria are naturally found in the environment and are particularly associated with water.

Legionnaires’ disease is caused by inhaling small droplets of water contaminated with Legionella bacteria.

Symptoms of Legionnaires’ disease

Symptoms usually appear within two to 10 days after breathing in the bacteria, and are similar to those of other types of pneumonia.

Symptoms may include the following:

• Fever
• Chills
• Cough
• Muscle aches and pains
• Headache
• Fatigue
• Loss of appetite
• Nausea and vomiting
• Diarrhoea
• Confusion or other mental changes

How is Legionnaires’ disease spread?

Legionella bacteria thrive in water and warm, damp places.

Common sources include soil, freshwater streams, lakes, pools and showers.

Research suggests the bacteria may also be present in water from sprinklers and in water reservoirs in car washes.

Outbreaks in Australia are generally associated with manufactured water systems, including water cooling towers and spa baths.

It is important to remember that although Legionella bacteria are commonly found in the environment, only a few people who come into contact with the bacteria become infected.

Who is at risk of getting it?

While anyone can contract Legionnaires’ disease, Assoc Prof Senanayake says certain groups are at higher risk.

“It tends to be more severe in older people, smokers and those with chronic lung and kidney disease,” Assoc Prof Senanayake says.

“Unfortunately, it can be fatal, especially in these groups.”

How common is Legionnaires’ disease?

In Europe, Australia and the USA there are about 10-15 cases detected per million population per year, according to the World Health Organisation.

However, University of Newcastle senior research fellow Dr Verlaine Timms says globally the incidence of Legionnaires’ disease has increased significantly, with notable rises in the USA and Hong Kong.

“This increase may be due to a growing number of susceptible individuals, better diagnostic methods, and improved reporting,” Dr Timms says.

Diagnosis and treatment

Diagnosing Legionnaires’ disease typically involves a combination of chest X-rays, urine tests, sputum tests and blood tests.

It is usually treated with antibiotics.

Early diagnosis and treatment are crucial to reduce the risk of severe complications.

Is Legionnaires’ disease contagious?

Assoc Prof Senanayake says Legionnaires’ disease is not contagious and cannot be spread from person to person.

According to the World Health Organisation, the most common form of transmission of Legionella is inhalation of contaminated aerosols from contaminated water.

Can Legionnaires’ disease be fatal?

Yes, if left untreated, Legionnaires’ disease can be fatal; and mortality rates are higher in older people and individuals with weakened immune systems, chronic lung disease, or who smoke.

What should you do if you suspect Legionnaires’ disease?

If you suspect you or someone you know has Legionnaires’ disease, seek medical attention immediately.

Early treatment is critical for recovery and reducing the risk of severe complications.

How long does it take to fully recover?

Recovery from Legionnaires’ disease can vary depending on the severity of the illness and the person’s overall health.

Most people will start to feel better within a few days of starting treatment, but some may experience lingering symptoms for several weeks or months.

Can Legionnaires’ disease recur?

While it is uncommon, it is possible for Legionnaires’ disease to recur, especially if the person has been re-exposed to contaminated water sources.

Maintaining good water hygiene practices is crucial to prevent a recurrence.

Is there a vaccine for Legionnaires’ disease?

Currently, there is no vaccine available for Legionnaires’ disease.

How to prevent Legionnaires’ disease at home

To reduce the risk of Legionnaires’ disease at home, it is recommended to flush hot and cold water through all tapping points at least once a week.

Home gardeners are encouraged to wear a face mask and gloves while handling potting mix and compost, and to wash their hands thoroughly.

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• Is your child at risk of RSV? What you need to know

Written by Bianca Carmona.