Six people fell ill between Nov. 18 and Nov. 23 and required hospitalization.
Officials are tracking the source of the exposure and believe the potentially deadly bacteria came from somewhere in the community.
Thirteen people died following an outbreak of legionnaires' disease in Quebec City earlier this year.
The source was later identified as a cooling tower in a city office building.
The bacteria grows in water and can be passed to humans through air conditioners, showers, fountains, humidifiers and hot tubs.