One person is dead and more than 40 people have become ill in an outbreak of legionnaires’ disease in London, Ont.
The Middlesex-London Health Unit, which declared the outbreak, said the cases were reported within the last week. Most of the people with the severe respiratory illness live and/or work within a six-kilometre radius of one another, in the southeast side of the city, officials said.
In a statement Tuesday, officials said the health unit is working closely with Public Health Ontario and the Public Health Ontario Laboratories to investigate and try to determine the source of the outbreak.
“Environmental sampling of potential sources of legionella is ongoing. Since legionella can be found in many types of cooling systems, the investigation may take time.”
This is the second outbreak of legionnaires’ disease in London since last summer. Last year’s outbreak was localized in the city’s east end and led to two deaths and 30 total reported infections.
“At this time, it is not known whether it [the current outbreak] is the same location as the legionnella outbreak from last year,” the health unit said. “However, this is being considered as part of the ongoing investigation.”
Legionnaires’ disease is caused by legionella bacteria, naturally found in water sources such as hot tubs, cooling towers, hot water tanks, large plumbing systems or parts of air-conditioning systems.
Legionella is not transmitted from person to person. If the bacteria are aerosolized or misted into the air (via wind or fans), people may inhale the bacteria and become unwell. Most people exposed to legionella don’t get ill, but some may experience Pontiac fever, a mild, flu-like illness that commonly resolves itself.
Individuals who are older, have lung problems or are immunocompromised (have a weak immune system) are at greater risk of serious infection.
Anyone who develops symptoms such as fever, cough and shortness of breath are encouraged to seek medical attention.
All business owners and property managers should ensure all cooling equipment is regularly maintained and sanitized as per the manufacturer’s instructions.
Although masks can decrease the risk of infection, the health unit is not recommending regular community-wide use of them specifically for the prevention of legionnaire’s disease, as the public risk is low.
