Hamilton Public Health says it has confirmed 13 cases of legionellosis, a serious respiratory infection caused by bacteria mainly found in warm water environments.
In a news release on Friday, public officials said the “cluster of cases” is focused in the East Hamilton and Stoney Creek area, with the first infection reported on May 4.
Hamilton Public Health said it is working to identify possible sources of exposure, including nearby cooling towers.
“We are working closely with local partners and reminding residents and facility operators of the importance of properly maintaining water systems and mist-producing devices,” said Hamilton’s associate medical officer of health Dr. Brendan Lew.
Public officials noted that hospitals have been notified to be on alert for potential cases.
Legionellosis is a group of infections caused by the Legionella bacteria. It could present as severe pneumonia, referred to as Legionnaires’ disease, or a mild flu-like illness called Pontiac fever.
It is not spread person to person but through inhalation of droplets containing the bacterium.
Symptoms include fever, chills, shortness of breath and cough.
According to the Public Health Agency of Canada, untreated Legionnaires’ disease usually worsens during the first week. Officials urged that once symptoms appear, people should consult their health care provider.
Earlier this week, Toronto Public Health (TPH) confirmed that it was investigating nine confirmed cases of legionnaires’ disease.
TPH said the outbreak is concentrated in the southeastern area of the city.
Last year, between Jan. 1 and Dec. 3, Ontario reported 354 cases of Legionnaires’ disease. Of those cases, 26 died.
Public Health Ontario indicated that cases usually peaked in the summer.


