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Water Today Title November 27, 2020

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Update 2018/2/7
Legionnaire's Disease


This story is brought to you in part by Biomass Recycle

By Michelle Moore

New research has surfaced linking the outbreak of Legionnaire's disease in Flint Michigan in 2014-2015 to the switch in the source of the public water supply. At least eighty-seven people were infected and twelve died in the third largest outbreak of Legionnaire's disease in United States history.

According to a report published in the Proceedings of the National Academy of Sciences, the risk of developing Legionnaire's disease increased over six fold for Flint residents after the city switched their water supply from Lake Huron to the Flint River. Changes in the water quality are cited as the cause of the outbreak.

The study indicates that after a boil water advisory was issued the situation did improve and once the water supply was switched back levels were normal. Researchers point specifically to the decrease in the levels of chlorine as having caused an increase in the risk of developing Legionnaire's disease. The study states, "during the switch, the risk of a Flint neighbourhood having a case of LD increased by 80% per 1 mg/L decrease in free chlorine, as calculated from the extensive variation in chlorine observed."

Legionnaire's disease is caused by a Legionella bacteria which can be found naturally in freshwater and rarely causes illness. In most cases, people become sick when the bacteria grows in man-made structures that hold water and are not properly maintained like cooling towers, hot water tanks, shower faucets, and large plumbing systems.

They can inhale the small droplets or aerosol that contains the bacteria and get infected. Dr. Walter Bradley is a Fellow of the Royal College of Physicians of London, he said "Legionnaire's disease is an area where aerosolization has been well documented. Cases that have occurred have been up to ten kilometres away from the water tower that was contaminated with Legionella."

The Centers for Disease Control and Prevention reports that most people who get infected will require hospitalization and recover but one out of ten people will die from the infection. Those infected develop a kind of pneumonia; early symptoms include fever, cough, muscle aches, headache and shortness of breath.

According to Health Canada, "the average number of reported cases of Legionnaire' disease in Canada is generally less than one hundred per year. However the actual number of cases is thought to be much higher, as many people with pneumonia may not be tested for infection with Legionella."

A study compiled by the National Microbiology Laboratory for the Public Health Agency of Canada stated that the multiple outbreaks in Canada have all occurred in summer and autumn. Between July and September 2012, thirteen people died and one hundred seventy cases were reported in Quebec City. During the months of September and October 2005, twenty-three people died and another one hundred twelve reported illness in Toronto. Both cases were found to be caused by cooling towers.


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