Legionnaires’ disease has made recent headlines in Ontario and neighboring New York state this summer. In London, Ontario, an outbreak in July resulted in three fatalities and 70 infections. The outbreak has been declared over, but the source remains unknown. In New York City, a recent outbreak since late July has claimed three lives and infected more than five dozen individuals. Health officials in New York City have linked the outbreak in Central Harlem to cooling towers, structures containing water and a fan used for building cooling. Although 11 towers initially tested positive for the bacteria causing Legionnaires’ disease, the issue has been resolved.
Legionnaires’ disease is a respiratory infection caused by the Legionella bacteria. Symptoms include fever, chills, and a dry cough, progressing to a serious chest infection or pneumonia with potential fatal outcomes. The disease’s name originates from a 1976 pneumonia outbreak at an American Legion Convention in Philadelphia.
Legionella bacteria live in various water sources, both natural and man-made, and can infect individuals through inhaling contaminated water droplets. Cooling towers, hot tubs, and plumbing systems can release mist containing the bacteria into the air. The disease is not transmissible between people. Cooling towers, commonly found in industrial air-conditioning equipment, can provide a conducive environment for Legionella growth and the spread of contaminated water droplets.
Outbreaks of Legionnaires’ disease are more common during warm weather, with risk factors including age over 40, smoking, chronic health conditions, and recent travel. The infection can lead to pneumonia, with severe cases requiring intensive care treatment. Antibiotics are the primary treatment, but severe cases may necessitate additional interventions due to the inflammatory response.
Prevention measures include proper maintenance of mist-producing devices and cooling towers to control Legionella growth. The risk of contracting Legionnaires’ disease is generally low, and most cases in Canada are sporadic. Previous outbreaks in Canada, such as the Quebec City outbreak in 2012, led to the introduction of regulations for cooling tower operation and maintenance to prevent future occurrences.