Five cases of Legionnaires' disease reported in Lexington, prompting health officials to urge caution around pools, hot tubs

Centers for Disease Control and Prevention graphic

By Melissa Patrick

Kentucky Health News

The Lexington-Fayette County Health Department announced Thursday that it has seen an increase in Legionnaires' disease this year and is warning people to take caution around outdoor pools and hot tubs, since the disease is spread when people breathe in small droplets of water that contain the bacteria that causes it. 

"The increase of use of outdoor pools and hot tubs during the summer, combined with recent rainfall and the potential for stagnant water, creates a need for reminders about Legionnaires’ disease," the department said in a news release. 

Kevin Hall, spokesperson for the department, told Kentucky Health News that five cases of the disease have been reported and that they typically don't have any. He added that they were still investigating the sources of the infections and that it is still unknown whether the cases ae related. 

Legionnaires' disease is a very serious type of pneumonia caused by Legionella pneumophil bacteria. The bacteria can also cause a less serious illness called Pontiac fever.

"Legionella occurs naturally in freshwater environments, like lakes and streams. It can become a health concern when it grows and spreads in human-made building water systems," the release says. 

For example, the Centers for Disease Control and Prevention says it can grow in shower heads and sink faucets, cooling towers, hot tubs, decorative fountains and water features, hot-water tanks and heaters and large, complex plumbing systems like those found in hospitals, hotels and cruise ships. (It was discoveerd after an outbreak at a Philadelphia hotel durign an American Legion convention.)

The health department adds that swimming pools become a concern when the temperature sits within the danger zone for the growth of the bacteria: "Legionella are unlikely to grow in typical swimming pools because water temperatures are usually too cold. However, you should sample pools if they are associated with a possible exposure or temperatures are within the permissive range (i77 to 113°F )." 

Health officials say the disease is generally not spread from person to person, but that is possible under rare circumstances. 

People at higher risk of getting Legionnaires' disease are those 50 and older, those with chronic lung disease, current or former smokers, those who take drugs that suppress their immune system, and people with cancer or underlying illnesses like diabetes, kidney failure or liver failure. 

The CDC urges people to talk to their doctor or local health department right away if they think they have been exposed to Legionella or if you develop pneumonia symptoms, such as fever, cough, chills or muscle aches. And, to be sure to mention if you have spent any nights away from home in the last 14 days. 

The health department says public-health agencies reported nearly 10,000 cases of Legionnaires’ disease in the U.S. in 2018, but thie actual number was likely much higher because the disease often goes undiagnosed: "A recent study estimated that the true number of Legionnaires’ disease cases may be 1.8–2.7 times higher than what is reported."

In Kentucky, 606 cases of  Legionnaires' disease (both confirmed and probable) have been reported since 2018, with an average of 114 cases a year between 2018 and 2021. In 2022, the state reported 107 cases, which are still being reconciled, and so far, 43 cases have been reported in 2023.  

While the disease is uncommon and most people make a full recovery, it can be deadly. According to the CDC, most people who get Legionnaires' disease need  hospital care, and about one out of every 10 people who get the disease die from complications of the illness.