Pontiac fever

Information for health professionals on the characteristics, diagnosis and treatment of Pontiac fever.

Pontiac fever is a mild flu-like illness caused by legionella bacteria. Symptoms can include fever, headaches and muscle aches but, unlike Legionnaires’ disease, Pontiac fever does not include pneumonia.


The illness is self-limiting and symptoms can include fever and at least one of the following:

  • headache
  • muscle aches
  • dry cough
  • shortness of breath

It is not clear why some people get Legionnaires’ disease (legionella infection causing pneumonia) and some people get the milder Pontiac fever when exposed to legionella bacteria. It is also thought that some people who are exposed to legionella bacteria do not become ill at all.


Legionella bacteria live in the natural freshwater environments of rivers, lakes, streams and ponds. They can also contaminate hot and cold water storage and distribution systems, and water in air conditioning and industrial cooling systems.

The disease spreads through the air from a contaminated water source. Breathing in aerosols from a contaminated water system such as spa pools is the main transmission route.


A urine test can diagnose sporadic cases of Pontiac fever. Most reported cases occur during legionellosis outbreaks.


There is no specific treatment for Pontiac fever.

Treat symptoms appropriately based on clinical assessment of severity. For most people, this is a self-limiting illness.

Published 22 November 2007
Last updated 24 July 2019 + show all updates
  1. Updated the guidance.

  2. First published.