Legionnaires Disease


What is legionella?


legionnaires disease

Legionella bacteria is found in damp or wet environments, especially in water between 20-45°C, potting mixes, composts, mulches, soil conditioners and gardening soils. The bacteria remain dormant in temperatures less than 20°C and cannot survive in temperatures above 60°C


What Is Legionnaires disease?

Legionnaires disease is a type of potentially fatal pneumonia contracted by breathing in legionella bacteria though airborne water droplets.

Anyone can contract legionnaires disease but some higher risk categories include:

  • People 50 years of age or above
  • People who smoke or have smoked heavily in the past
  • People who drink alcohol heavily
  • People with underlying medical conditions, such as diabeteskidney disease, or  pre-existing lung conditions
  • People who have a weakened immune system  from diseases such as HIV and AIDS or cancer


What Is The Legionella Risk In My Home?

Any water system under the right conditions could be a source of legionella bacteria, especially if your water system:

  • Holds water between 20–45 °C
  • Creates and/or spreads breathable droplets
  • Stores and/or re-circulates water
  • Contains a source of nutrients, e.g. sludge, rust, scale and organic matter for the organism to grow

legionella is commonly found in man-made water systems including:


Signs And Symptoms Of Legionnaires disease

Legionnaires’ disease usually develops two to 10 days after exposure and commonly includes the following symptoms:

Day 1-2

  • Headache
  • Muscle pain
  • Chills
  • Fever – May be 40 °C or higher

Day 2-3

  • Cough, (can cough mucous or blood)
  • Shortness of breath
  • Chest pains
  • Nausea, vomiting and diarrhea
  • Confusion or other mental changes

Although legionnaires’ disease generally affects the lungs, it can cause infections in other parts of the body, including the heart.


Pontiac fever

A more mild form of legionnaires’ disease is Pontiac fever,  although Pontiac fever has similar symptoms including fever, chills, muscle aches and pains and a headache it does not infect your lungs, and symptoms usually last 2-5 days.


Legionnaires Disease Treatment

If you present with any of the above signs and symptoms it is important to see your doctor immediately as the only treatment for legionnaires disease is a course of antibiotics.

Depending on the severity of symptoms treatment can last between 1 and 3 weeks.


Legionnaires disease Prevention


When Handling Potting Mixes And Garden Soils:

  • Wear gloves
  • Wear a mask to prevent inhaling aerosols
  • Carefully open bags to avoid inhaling airborne particles
  • Dampen the mix while in use
  • Wash your hands thoroughly after use
  • Store potting mixes and soils out of the sun


Evaporative Air Conditioners

Before summer:

  • Disconnect power to the unit
  • Clean or replace filters
  • Clean and scrub all accessible waterways, including the bleed-off system
  • If required close drains and fill with clean water.
  • Disinfect the unit with a chlorine-based household bleach.

At the end of summer:

  • Disconnect power to the unit
  • Brush clean any sediment and slime
  • Drain all water from the unit
  • Clean the tank and pump with a chlorine-based household bleach then flush with clean water
  • Clean or replace filter pads
  • Dry all internal components
  • Make sure the water supply is clean and fresh


Portable evaporative coolers

Drain and clean at least once during hot weather and leave the unit to dry


Refrigerated air conditioners

Refrigerated/reverse cycle and split systems remove heat and moisture from the air without using water. They do not hold Legionella bacteria.


Domestic hot water systems

  • Must store water above 60°C but be mindful of the temperature to reduce scalding risks.
  • Regularly clean shower heads.



  • Regularly drain, clean and disinfect


Nebulizers and humidifiers

  • Rinse nebulizer bowls after each use and wash the mask and chamber in dish washing liquid
  • Allow to dry thoroughly
  • Clean or replace filters frequently


Spa baths

Regularly clean and disinfect