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Seven Oaks nursing home in Toronto

Another person has died after an outbreak of legionnaires' disease in Toronto, raising the number of dead to 21.

Toronto health officials say an 89-year-old woman died Monday morning in hospital.

She was a resident of the Seven Oaks nursing home.

Last week investigators confirmed the outbreak originated in the nursing home's air conditioning cooling tower when contaminated droplets were distributed into the air by the cooling system and then sucked into the ventilation system's air intake.

The cooling tower was ordered shut down on Oct. 6.

Legionnaires' disease is a form of pneumonia and is usually contracted by inhaling mist from water sources such as whirlpool baths, showers and cooling towers that are contaminated with legionella bacteria.