There is a greater emphasis on the role that climate change can play in the spread of legionaries such as London, Ontario, deals with its second deadly outbreak since the summer of 2024.
Some scientists point out the warming temperatures of the earth and changing climatic patterns, some of the climate change signs, such as an important role in the acceleration of growth and propagation of Legionella, the bacteria that cause serious respiratory condition.
The Canada Public Health Agency (PHAC) says that Legionella infection rates have increased dramatically, particularly between 2004 and the present. Experts also say that most infections are never reported.
“We are seeing these increases in cases, but is that because we are better to find the cases or there is something that happens out there that is causing more increases in the growth or dispersion of the bacteria?” Juliette O’Keeffe said, a senior scientist based in Vancouver with the National Environmental Health Collaboration Center.
In the case of London’s outbreaks that have led to the death of six people, the Middlesex-London Health Unit (MLU) identified an industrial cooling tower in the east of the city as a probable source.
Legionella are bacteria transmitted by water that thrive in warm, humid and stagnant conditions. When they aerosolize, these bacteria can be inhaled.
Inhalation sometimes causes legionellosis, which varies from a mild disease commonly called Pontiac fever to legionary disease.
O’Keeffe believes that his research has progressed in the identification of possible explanations for the rapid propagation of Legionella.
“The temperature is definitely a driver. If you have more warm days, it will have more conditions that are favorable for the growth of Legionella,” he said, pointing between 25 and 45 ° C as ideal.
Warm temperatures can also promote the spread of the bacteria, said Okeeffe, noting that most outbreaks are linked to cooling systems.
The highest temperatures mean more hours that pass cooling systems and the need to build more of them.
Other climatic factors also come into play when it comes to the propagation of Legionella, including moisture: more cases are informed in warm and humid areas of Canada, such as southwest Ontario and the East Coast.
“Legionella is scattered from the cooling towers in aerosols: small water bubbles that disperse over an area. When you have a humid atmosphere, they persist better,” O’Keeffe said.
A Health Canada report published in 2022 lists Legionella several times as a strong potential to be affected by climate change.
There is also an investigation that has established a link between some of the climate change signals (such as the heating, precipitation and humidity climate) and the propagation of bacteria.
For its part, the MLU mentioned the changing environment as a concern during a recent interview with CBC News, when the health unit reported the link between the London Legionnaires outbreaks and the Sofina Foods Inc cooling tower.
The outbreaks have no borders
Legionnaires disease and Legionella’s spread are also a concern in the United States, said Joan Rose, the president of Homer Nowlin in Water Research and the director of the Water Alliance of the State University of Michigan.
Legionella is “one of the pathogens transmitted by the most important water we are dealing with now,” said Rose, who has been studying water microbiology for about 40 years and observed in line worries with O’Keeffe.
“The outbreaks have increased, but most importantly, cases [in general] They have increased, “he said.” Of course, we are improving in the diagnosis, but we believe that this is a true increase in the incidence of the disease. “
Rose and O’Keeffe said the most frequent rain could play a role.
The research shows that rain events are correlated with legionellosis outbreaks in some areas, O’Keeffe said. He said that although the reasons for that are not clear, he suspects that he is related to the movement of water.
“Legionalla occurs naturally in groundwater and surface water. When you have these events, it mobilizes bacteria, it encourages them to start growing.”
London tomorrowA warmer climate could lead to more legionaries outbreaks
London is dealing with an outbreak of legionaries’ disease, something that is happening more frequently in North America and Europe. Joan Rose, director of the Water Alliance of the Michigan State University, joined London Morning to talk about how the bacteria spread and what can be done to avoid future outbreak situations.
To better control the growth and spread of Legionella, Rose and O’Keeffe, they suggested more research on effective disinfection and stricter regulations.
Quebec, New Brunswick, Hamilton and Vancouver, for example, have strict registration and safety requirements for cooling towers, while Ontario is among the jurisdictions that do not.
“We do not have many regulations that analyze how we monitor, so how we report information about this bacterium,” Rose said, echoing feelings that other experts have shared with CBC.
“That is one of the main things we can do,” O’Keeffe said. “This is not really so new. We know that cooling towers are a source. We know that keeping them well is a way to reduce exposures and maintain that water clean.”
