Legionnaires’ disease: Key symptoms and risks

A deadly legionella outbreak in Sydney has sparked alarm. See key symptoms of the disease, the risks and how to prevent an outbreak in your home.

A Legionnaires’ disease outbreak in one of Australia’s largest cities has sparked alarm with authorities warning people to be on alert for symptoms.

The outbreak in Potts Point in Sydney has already claimed one life and left six others hospitalised since late May.

Five of the other affected individuals have since been discharged from hospital, while one remains under treatment.

Here is what you need to know to know about the deadly disease:

WHAT IS LEGIONNAIRES’ DISEASE?

Legionellosis, also called Legionnaires’ disease, is an uncommon severe and sometimes life-threatening form of pneumonia, or lung inflammation caused by Legionella bacteria. It’s considered a respiratory condition and currently there is no vaccination against it available. Legionnaires is a nationally notifiable disease in Australia, meaning if a person is diagnosed with the disease it must be reported to the relevant health authorities. This is because it can cause severe illness and can occur in clusters or outbreaks.

Legionnaires' disease. Picture: Supplied/ Janice Haney Carr/ Public Health

HOW DO YOU KNOW IF YOU HAVE LEGIONELLA?

You may develop flu-like symptoms between two and 10 days after exposure to legionella bacteria. These include:

- fever and chills;

- cough;

- shortness of breath;

- muscle aches and headaches;

- fatigue;

- loss of appetite;

- diarrhoea or vomiting.

CAN LEGIONNAIRES’ BE SPREAD FROM PERSON TO PERSON?

No, you cannot catch Legionnaires’ disease from other people or contact with animals. But certain people are at greater risk of getting the disease after exposure to contaminated water systems. These include smokers, people with chronic illness such as diabetes and cancer; people with a chronic immune suppression (for example if you take steroid medicines for a health condition); if you are aged over 50.

WHAT IS THE MOST COMMON WAY TO GET LEGIONELLA?

Legionnaires’ disease is caused by breathing in dust or water vapour contaminated with legionella bacteria. You may be exposed to the bacteria at home, work or in public places.

Outbreaks often have a common source of infection, for example, a single air-conditioning cooling tower.

Cooling towers are often behind legionnaires’ outbreaks. Picture: Marc Robertson

IS LEGIONELLA IN TAP WATER?

Legionella is an organism that is ever-present in the environment and found in very low concentrations in the potable water supply (i.e. tap water). In the right environment, however, the Legionella bacteria can multiply and pose significant risks to the health of individuals exposed to the bacteria.

Victoria’s health authorities for have detected legionella in water delivery systems associated with showers and ice machines in hospitals and aged care facilities and car washes.

DOES BOILING WATER STOP LEGIONELLA?

Yes. Legionella bacteria thrive in water temperatures between 20-45C. Above 60C, they are rapidly killed. That’s why hot water systems are designed to store water at 60C or higher, according to Queensland Health. The treatment is known as pasteurisation.

HOW TO CONFIRM LEGIONNAIRES?

It is often difficult to distinguish Legionnaires’ disease from other types of pneumonia by symptoms alone. Chest X-rays help diagnose pneumonia but the diagnosis of Legionnaires’ disease requires special tests. Urine, sputum and blood samples can help confirm the diagnosis. Blood samples need to be taken three to six weeks apart to check on antibodies in the blood.

The Potts Point district in Sydney where an outbreak has claimed one life and left others seeking hospital treatment.

HOW TO TEST LEGIONELLA AT HOME?

you can purchase a Legionella water testing kit online, collect water samples from various sources like taps and showers, and then send the samples to a laboratory for analysis. The lab will provide results indicating the presence and concentration of Legionella bacteria.

If you are a smoker, quit, to help reduce your risk as your are at greater risk of being exposed to airborne legionella bacteria.

DOES LEGIONNAIRES’ DISEASE GO AWAY ON ITS OWN?

No. You should visit your doctor immediately if you suspect you have been exposed to legionella bacteria or have symptoms of the illness. Legionnaires’ disease is generally treated with antibiotics. If you develop severe symptoms, you may need to be hospitalised.

WHAT ARE THE LONG TERM EFFECTS OF THE ILLNESS?

Legionnaires’ can cause severe pneumonia that may need treatment in hospital or an intensive care unit (ICU). In rare cases, Legionnaires’ disease is fatal. Tests show that your body is able to develop immunity against a second infection but how long immunity lasts is unknown.

HOW TO PREVENT LEGIONNAIRES’ DISEASE AT HOME?

To minimise the risk of the disease at home, Australian guidelines emphasise regular maintenance and cleaning of water systems, proper handling of potting mix, and being mindful of potential aerosol exposure. This includes disinfecting evaporative air conditioners, cleaning and draining spa baths, and using sterile water in nebulisers and humidifiers.

Sources of information Health Department and Health Direct.

Originally published as Legionnaires’ disease: Key symptoms and risks