Legionella longbeachae is a Gram-negative bacterium, found predominantly in potting soil and compost. In humans, the infection is sometimes called Pontiac fever.
Human infection from L. longbeachae is particularly common in Australia, but cases have been documented in other countries including the United States, Japan, Greece and the UK.
The infection can be very serious, often leading to hospitalisation and sometimes death. Early symptoms include fever, chills, headache, shortness of breath, sometimes dry cough, and muscle aches and pain.
Most people who breathe in the bacteria do not become ill. The risk of disease is increased with age, smoking, and in people with weakened immune systems.