BERTHIERVILLE, Que. -- The provincial Health Department is investigating an outbreak of legionnaires' disease that has claimed two lives.

There have been 16 other confirmed cases since Aug. 20., all in the town of Berthierville, about 80 kilometres northeast of Montreal.

Legionnaires' disease is contracted by breathing in small droplets of water contaminated with bacteria.

The deadly bacteria grow in the stagnant water of cooling systems and spread in droplets through air conditioning.

Authorities believe the source of the outbreak was in the cooling system in the town's arena.

The system was shut down as of Aug. 22, but because the incubation period is 10 days, authorities believe new cases may continue until early September.

Symptoms include coughs, fever, chills and respiratory problems.

Most people have little to no risk of catching the disease, which is not contagious and cannot be transmitted from one person to another.

The elderly, however, are more vulnerable to an outbreak, as are heavy smokers and people with weak immune systems.

An outbreak of legionnaires' disease claimed 14 lives in Quebec City in 2012.