Legionnaires’ disease produces symptoms similar to pneumonia, including:
- loss of appetite
- muscle pain
- headache, followed by:
- high fever
- abdominal pain, and
Symptoms start an average of 5 to 6 days (range 1 to 19 days) after exposure to the bacteria.
Pontiac fever causes mild symptoms of:
- headache, and
- muscle aches that go away without serious problems.
Symptoms start an average of 24 to 48 hours (range 5 to 66 hours) after exposure to the bacteria. Sometimes a person can be infected and have no symptoms. People at most risk of infection and serious illness from a legionella infection are those over the age of 65, smokers, those who have a lung disease such as emphysema and those whose immune system is compromised.