Legionnaires’ Disease Cases Hit 10-Year High in Florida Following Gym Outbreak
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Dec. 6,2025,12:46 p.m. ET
An outbreak of Legionnaires’ disease cases linked to a Florida gym has brought cases to a 10-year-high in the state.
The Orange County “gym exposure” outbreak includes 14 cases of the disease,the Florida Department of Health said.
Legionnaires’ disease is a serious type of pneumonia caused by the Legionella bacteria, according to the health department. The lung infection can be mild for healthy people but serious and sometiems deadly for certain at-risk groups.
“The most common way for someone to get sick is by breathing in mist containing Legionella,” according to the U.S. Centers for Disease Control and Prevention.
The gym outbreak brings the total number of cases in Orange County in 2025 to 82,the highest in the state. Florida reported a total of 72 confirmed legionellosis cases in November. Florida has seen 665 cases in 2025.
Previously: an obscure disease keeps spreading through air conditioning
Legionellosis case reports also include pontiac fever, which is a milder infection caused by the same type of Legionella bacteria that causes Legionnaires’ disease.
Florida’s uptick in Legionnaires’ cases mirrors a national trend,according to the U.S. Centers for Disease Control and Prevention. Here’s what to know about the illness:
What is Legionnaires’ disease? What are the symptoms?
Most healthy people exposed to Legionella don’t get sick or exhibit the milder Pontiac fever.Older adults and people who smoke have a higher risk of contracting the more serious Legionnaires’ disease cases and should seek immediate treatment.
The first signs of Legionnaires’ disease tend to mimic the flu.People frequently enough develop a high fever,headaches and muscle aches between two and 10 days after contact with Legionella b
Legionnaires’ Disease Cases rising in the U.S., Linked to climate Change and Infrastructure
Legionnaires’ disease, a severe form of pneumonia caused by the Legionella bacteria, is experiencing a meaningful increase in cases across the United States.While cases dipped during the COVID-19 pandemic,they have rebounded and are now on the rise,with a particularly concerning outbreak in New York City in 2025. This increase is linked to factors including aging populations,regional vulnerabilities,and the impact of climate change on water systems and cooling infrastructure.
Who is at Risk?
Certain populations are more susceptible to contracting Legionnaires’ disease. According to the Centers for Disease Control and Prevention (CDC), those most at risk include:
* Smokers (current or former)
* People with chronic lung disease (like COPD or emphysema)
* Individuals with weakened immune systems
* People with certain medical conditions, such as diabetes, kidney failure, or cancer.
Geographically, cases are more prevalent in the Northeast and Midwest regions of the U.S., and typically peak during the summer and fall months.
Recent Trends and Outbreaks
As 2000, the U.S. has seen a ninefold increase in legionellosis rates. While 2020 saw a five-year low in reported cases, likely due to pandemic-related factors, numbers have been climbing as 2021.Between 8,000 and 18,000 Americans are hospitalized with Legionnaires’ disease annually, according to various state health departments.
A significant outbreak occurred in the summer of 2025 in Central harlem, New York City. This cluster resulted in at least seven deaths, 90 hospitalizations, and 114 confirmed cases. The outbreak was traced to cooling towers harboring the bacteria, and officials took action to remediate issues across five zip codes. The New York City Department of Health and Mental Hygiene declared the cluster over on August 29, 2025.
The role of Climate Change
Experts are increasingly pointing to climate change as a contributing factor to the rise in Legionnaires’ disease cases. Warmer temperatures and increased humidity create ideal conditions for the Legionella bacteria to thrive. Furthermore, these conditions drive increased use of cooling systems – such as cooling towers – which can become breeding grounds for the bacteria if not properly maintained. The CDC specifically identifies warmer water temperatures as a key factor in bacterial growth and spread.
Understanding Legionnaires’ Disease
Legionnaires’ disease is not contagious from person to person. It is indeed contracted by inhaling microscopic water droplets containing the Legionella bacteria. Sources of infection can include:
* Hospital and healthcare facilities water systems
Symptoms typically include pneumonia, fever, cough, shortness of breath, muscle aches, and headaches. Early diagnosis and treatment with antibiotics are crucial for recovery.
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