The Simcoe Muskoka District Health Unit is actively investigating a cluster of Legionnaires’ disease cases in the Orillia area, with 19 confirmed cases to date.
Cases have been confirmed in individuals between 52 and 87 years of age, who either reside in Orillia or have visited the city over the past several weeks.
The cases were reported to the health unit over the past three days, beginning Oct. 4, with health unit officials saying a cluster of 19 cases is unusually high for Orillia.
“It is a lot, to put it bluntly,” said the region's associate medical officer of health, Dr. Colin Lee. “In Simcoe Muskoka … the last few years, it's been about 10 (per year).”
Among the confirmed cases, the earliest someone experienced symptoms was Sept. 19, Lee said, with the most recent in early October.
“The incubation period, the period (when) you get infected until you show symptoms, for Legionella is around two to 10 days,” Lee said, adding that exposure for the current cluster likely took place in the first three weeks of September.
All individuals were tested in hospital and were or still are hospitalized. None have required ICU care.
This is not the first time the lung disease has been prevalent in the community. There was an outbreak in Orillia in the fall of 2019, linked to the cooling tower at Rotary Place. There were 10 confirmed cases during that incident.
“At that time, the investigation revealed that it was most likely a cooling tower,” Lee said. Therefore, this time around, given that the cases are clustered quite closely in time, and with no real commonalities easily identifiable – it’s (from) all over Orillia – it's likely a cooling tower. That's where we are focusing both our investigation and remediation of those potential sources.”
Lee said the health unit is aware of nine cooling towers in the city.
Although the investigation is in its early stages, with no source of infection determined, Lee said the health unit is taking a "proactive" approach to its investigation.
“We are currently asking and contacting them to immediately remediate them, through cleaning and disinfection, in the event any of those nine cooling towers are harbouring Legionella, while also testing the water there for Legionella,” Lee said.
“It should be noted that for most Legionella clusters in cases anywhere in the world, they don't usually find a source because the sampling, testing is complex; the results take days to weeks; the source may no longer be there," Lee told OrilliaMatters.
“We're not waiting for those test results. We're proactively approaching the cooling towers and asking them to be cleaned and disinfected as soon as feasible to decrease the risk as much as possible, as quickly as possible.”
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.
Legionnaires’ disease is a type of pneumonia (lung infection) caused by the bacteria. 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, are at increased risk for Legionnaires’ disease. Legionnaires’ disease can be treated with antibiotics and most cases resolve without long term effects.
