Estimating the burden of illness caused by domestic waterborne Legionnaires' disease in Canada: 2015-2019.

Legionellosis is a disease caused by the bacterium that most commonly presents as Legionnaires' disease (LD), a severe form of pneumonia. From 2015 to 2019, an average of 438 LD cases per year were reported in Canada. However, it is believed that the actual number of cases is much higher, since LD may be underdiagnosed and underreported.