BARRIE – An investigation by the Simcoe Muskoka District Health Unit (SMDHU) into an increase in Legionnaires’ disease cases in Barrie, first announced December 11, is now concluded.

“People generally develop symptoms two to 10 days following exposure to the bacteria, and it’s now been more than a month since the onset of the last case. Based on this, as well as the fact that none of the cooling towers that were investigated within a wide radius of the cases were found to be the source of infection, we have concluded that the increase in Legionnaires’ disease has ended,” said Dr. Charles Gardner, Medical Officer of Health for the Simcoe Muskoka District Health Unit. “We do not anticipate further spread of the disease associated with these cases.”

Despite an intensive investigation, SMDHU has been unable to determine the source or sources of the bacteria. This is not unusual in Legionnaires’ disease investigations, in which finding a common environmental source of the bacteria is known to be difficult and complicated.

The investigation began with four cases of the disease; a fifth case was identified following a notice to health care providers to watch for and test potential cases. SMDHU began its investigation into the cases because it is atypical to see this number of cases at this time of year. The health unit usually sees on average two cases of Legionnaires’ disease in Barrie residents every year, and cases most commonly occur in summer and fall.

Legionnaires’ disease is a lung disease caused by Legionella bacteria, which is commonly found in natural freshwater environments. However, it can become a health concern in water systems, such as cooling towers, plumbing systems in large buildings and certain medical devices when conditions allow the bacteria to multiply.

People can develop Legionnaires’ disease when they inhale aerosolized water droplets containing the bacteria. People cannot get Legionnaires’ disease by drinking water and it cannot be passed from person to person. Most people exposed to the bacteria do not become ill. Those at increased risk of the disease are people over the age of 50, smokers, or those with certain medical conditions, including weakened immune systems, chronic lung disease or other chronic health conditions.

For more, see www.smdhu.org or call Health Connection at 705-721-7520 or 1-877-721-7520, weekdays from 8:30 a.m. to 4:30 p.m.

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