Legionnaires’ disease: what you need to know

World-renowned microbiologist and CEO of Hudson Institute of Medical Research, Professor Elizabeth Hartland, share what you need to know about Legionnaires’ disease – where it comes from and how to avoid it.

Legionnaires’ disease is a form of pneumonia that is environmentally acquired and not transmitted from person to person.

Symptoms are similar to flu and COVID, including fever, chills, cough and fatigue. The disease is caused by Legionella bacteria that are naturally occurring in water and soil. Legionella live as a parasite and replicate in environmental amoebae and use similar mechanisms to replicate in the human lung.

Contaminated water can grow Legionnaires bacteria

In contaminated water that is held at higher than ambient temperature, such as cooling towers, spas, fountains and car washes, the bacteria can grow to high numbers in aerosolised water droplets which can then be inhaled. Disease symptoms can appear up to 14 days after exposure.

People who develop severe disease usually have other risk factors such as underlying lung damage, advanced age or immune suppression. Antibiotic treatment is generally successful if the disease is accurately diagnosed early.

Professor Elizabeth Hartland | International Legionnaires’ disease authority

Professor Elizabeth Hartland AM is the Director and CEO of Hudson Institute of Medical Research in Melbourne and Head of the Department of Molecular and Translational Science at Monash University. She is President of the Australian Association of Medical Research Institutes (AAMRI) and a member of NHMRC Council (2021-2024).

She is a leading Australian microbiologist with a long-standing research interest in the immune response to infection with an emphasis on microbial evasion of innate immunity. Professor Hartland’s research group’s work on Legionella examines how the bacteria remodel human immune cells to replicate in the lung and avoid killing by the antimicrobial immune response.