Legionella longbeachae infection - including symptoms, treatment and prevention

Many different species of bacteria called Legionella are commonly found in the environment and some of these are known to cause illness in people. Infection by Legionella causes a disease known as legionellosis.

Legionella longbeachae infection is a notifiable condition1

How Legionella longbeachae is spread

Legionella longbeachae (L. longbeachae) can be found in potting mixes, compost heaps and composted animal manures. How L. longbeachae are spread is uncertain, but it is thought that they are breathed in or spread from hand to mouth. The bacteria can remain on hands contaminated by handling potting mix for periods of up to 1 hour. They can be readily removed from the hands by washing. Legionella infection cannot be caught from other people or animals. The risk of L. longbeachae infection is not limited to gardeners, but the use of potting mixes, composts and other soils puts them at greater risk.

Signs and symptoms of Legionella longbeachae infection

L. longbeachae generally causes infection of the lung (pneumonia), which is a severe illness.

Symptoms of Legionella infection may include:

  • fever
  • cough
  • chest pain
  • breathlessness
  • diarrhoea.

People of any age may be infected, but the disease is more common in middle aged and older people and people whose immune system is weak. Men are affected more frequently than women.

Risk of infection is increased by:

  • smoking
  • chronic heart or lung disease
  • diabetes
  • kidney failure
  • some forms of cancer
  • immunosuppression, especially if on steroid medication
  • being 50 years or older.

Diagnosis of Legionella longbeachae infection

Diagnosis is usually made by a series of blood tests. The bacteria may sometimes be grown from a sample of sputum (phlegm) or lung fluid, or detected using other special tests.

Incubation period

(time between becoming infected and developing symptoms)

2 to 10 days, usually 5 to 6 days.

Infectious period

(time during which an infected person can infect others)

Person-to-person spread does not occur.

Treatment for Legionella longbeachae infection

Antibiotic treatment may be prescribed by the treating doctor. Some cases may require admission to hospital.

Prevention of Legionella longbeachae infection

Exclusion from childcare, preschool, school or work is not necessary.

To minimise the risk of exposure when handling garden mixes (bagged or unbagged) such as potting mix, mulches, composts and garden soils, gardeners should take the following precautions:

  • read the warning on bagged mixes and follow the manufacturer’s instructions
  • avoid inhaling airborne particles such as dust or mists
  • avoid hand-to-mouth contact
  • open bagged mixes in a well-ventilated space
  • moisten the garden mix, avoiding the inhalation of airborne particles
  • always wash hands after using garden mixes, even if gloves have been worn
  • store bagged mixes in a cool dry place.

Additional measures that can be taken to reduce risk include wearing a face mask and gloves.

Useful links

1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.