A concerning outbreak of Legionnaires’ disease in New York City has led to several deaths and hundreds of infections this summer.
In late July, an outbreak of the infection in Central Harlem was detected. Since then, six people have died and over 100 residents have been diagnosed with the disease in more than one zip code in the area.
On Tuesday, health officials announced an investigation on an apartment complex in the Bronx following two positive cases of Legionnaires’ disease.
A deadly outbreak of the disease was also detected in London, Ontario, resulting in four deaths and almost 90 hospitalizations this July. Health experts worry that as the planet gets warmer, cases of the infection will multiply.
“Legionnaires’ disease is a pneumonia that is caused by a bacteria called Legionella,” says Dr. Roy Gulick, chief of the division of infectious diseases at Weill Cornell Medicine and attending physician at NewYork-Presbyterian Hospital.
Legionella lives in dirt and water, and typically likes still, warm water like the water in cooling towers for air conditioning systems, Gulick explains.
“If there’s water that’s been sitting there for a while, it’s a prime place for this bacteria to be,” he says.
“Then, when you turn on your air conditioner and the fan, it can aerosolize the water, meaning it can throw particles of water into the air. So a person who’s walking by the air conditioner, and breathes in those particles, will be exposed to Legionella.”
If you’re wondering how concerned you should be about the spread of Legionnaires’ disease, we asked Gulick and Dr. Michael Phillips, chief hospital epidemiologist for NYU Langone Health, about symptoms to look out for and how to stay protected.
Here’s what you need to know about Legionnaires’ disease
Thankfully, Legionnaires’ disease can not be spread from person to person, according to both experts. In addition to air conditioning systems, Legionella can live in hot tubs and even fountains that people have outside of their homes, Gulick says.
Not everyone who is exposed to Legionella develops symptoms. Reactions to exposure can range from no symptoms at all to needing to receive intensive care in the hospital, depending on the person, Gulick says.
“People walking around their neighborhoods could be exposed just from breathing in the air and not know that they’ve been exposed to Legionella,” he adds.
“Most people who are exposed don’t actually develop disease. There are certain groups that are at greater risk.”
People who have a higher chance of developing Legionnaires’ disease from exposure to Legionella are:
Those with compromised immune systems, or who take medicines that can suppress their immune systemPeople over the age of 65SmokersPeople with lung disease
Legionella causes between 1% to 10% of all pneumonias, Gulick says. Typically, health professionals see an increase in cases between mid-summer and early fall, he notes, when people are using air conditioners more.
Symptoms and treatments of Legionnaires’ disease
According to the Centers for Disease Control and Prevention, symptoms of Legionnaires’ disease can include:
FeverCoughMuscle achesHeadachesShortness of breath
“There are no vaccines for Legionella. There are no medications that would be prescribed to prevent Legionella [exposure],” Gulick says.
But once contracted, Legionnaires’ disease can be detected through multiple tests like laboratory swab tests or urine tests, the CDC states.
There are also very effective antibiotics that can cure the disease. The challenge is that “the most common antibiotics we often use for pneumonia are not effective against Legionella,” Gulick says. Specific antibiotics are needed to treat Legionnaires’ disease which is why community awareness is important to detect outbreaks.
“In the summer, there’s a greater risk of this infection, and there are specific antibiotics and ways of detecting it,” Phillips says. “It’s well known in the medical community what to do, but I also feel that patients need to understand that.”
How to be proactive during a Legionnaires’ disease outbreak
As a first step, detecting where Legionella exists is important to decrease the chances of it spreading.
“Building owners and managers can use a water management program to help control Legionella,” according to the CDC.
For at-risk individuals, Phillips suggests being aware of any symptoms like shortness of breath or fever and seeking medical attention as soon as possible. Be sure to ask for appropriate testing for Legionella detection.
“There’s no formal recommendation to mask, but people who are at higher risk, so older people or those with underlying conditions, may want to consider it. Particularly if you live in Central Harlem right now and you’re going out just walking on the street,” Gulick says.
“There’s no downside to it, and potentially there’s an upside to avoid this.”
Phillips says that only a respirator like a KN95 or N95 mask would be able to prevent infection, but says it may not be necessary to wear one because the average risk of developing Legionnaires’ disease is pretty low.
Regardless of medical history, “if people develop a fever or a cough and things are persistent for more than a day or two, they should seek medical attention,” Gulick says.
“And if someone develops shortness of breath, that is a warning sign that they need medical attention.”
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