The City of Hamilton’s Public Health Services reports there are increasing cases of Legionnaires’ disease, a type of pneumonia that is caused by legionella, a bacterium found primarily in warm water environments.

Public Health has received reports of six cases since the beginning of July, which the city reports is high for the expected number of cases for this time period. The investigation is focused in the east end of the city.

The investigation is determining possible sources of exposure for each case. While the investigation is ongoing no common source is suspected to be the cause of these infections. When looking for sources of exposure, items of concern include air conditioning systems, water cooling towers, humidifiers and hot tubs and spas

“While legionella is ubiquitous in the environment it is often a summertime phenomenon – especially during warm, humid summers,” said Medical Officer of Health Dr. Elizabeth Richardson. “The risk to the broader community is low. Those at highest risk for infection are aged 50 or older and people with weakened immune systems. As we continue our investigation to seek out potential sources, we remind residents to ensure all mist-producing devices, such as showerheads, hot tubs, whirlpools and humidifiers are regularly maintained.”

As a preventive measure, Public Health Services has communicated with all cooling tower owners and operators reminding them of the importance of maintaining their cooling tower(s) to minimize legionella growth. Local health care providers have also been notified of the local legionella activity so that they can take any appropriate action with their patients.

The bacterium that causes Legionnaire’s Disease is commonly found in the environment. The disease is not spread person to person, but rather occurs when a susceptible person inhales droplets containing the bacterium.