What is Legionnaires' disease?

Disease can be deadly, but it's not spread from person to person

Stock photo

Most recently making headlines, officials with a health board in Ohio said 11 cases of Legionnaires’ disease have been confirmed in a Cleveland suburb, with one death reported.

Eight cases were also identified in a New York City neighborhood just last month. Additionally, Legionnaires' disease has been connected to the deadly Flint water crisis. And health officials in Illinois say it contributed to the deaths of 13 people at a state-run veterans home. The bacteria that causes it also was found at a building on a college campus in Michigan earlier this summer.

Well, in case you haven’t been following the headlines over the past few weeks or even recent years, we thought we'd examine the disease. As for what exactly it entails -- and why is it called Legionnaires', anyway? -- let’s take a look.

What is Legionnaires’?
The disease, a pneumonia-like illness, is caused by waterborne bacteria inhaled from vapor. Symptoms often start two to 10 days after exposure and include diarrhea, nausea, vomiting, aching muscles, fever and chills.

I've heard of legionella. What's that?
Legionella is the bacteria that causes the disease. It's often found in the water, if the temperature and chemical conditions are right.

Where did these names come from?
Twenty-nine people died in an outbreak in 1976, at an American Legion convention in Philadelphia. Hence, Legionnaires’ disease.

What are the symptoms?
These can include fever, muscle aches, nausea, chills, vomiting, headaches and coughing. They usually kick in anywhere from two to 10 days after exposure to the bacteria.

Is Legionnaires' contagious?

Then how does it spread?
The disease doesn’t pass from person to person, but it does travel through mist, such as the kind that comes from hot tubs or air conditioning units.

Why is the disease in the news lately?
The state of Michigan, for example, in July issued a warning about legionella-related illnesses being on the rise. The state has seen a nearly 30 percent spike this year in the number of people who contracted legionellosis, which includes Legionnaires' disease and the milder Pontiac fever, compared with this time in 2017, according to data released by the Michigan Department of Health and Human Services. The statewide uptick in cases follows a national trend, a health department spokeswoman said.

So is this considered an outbreak right now?
No, it does not qualify as an outbreak at this time.

How does the weather factor in?
Many parts of the country are currently seeing long stretches of hot and humid conditions. And the best environment for bacterial growth is in warm, stagnant waters -- which come with the hot temperatures. Legionella-related illnesses almost always are higher in the summer and early fall, according to published reports.

Should I be concerned?
For most people, it’s just something to be aware of. There’s no need to panic. However, Legionnaires’ can be especially dangerous for people who are elderly, who smoke or used to smoke, or who have compromised immune systems or chronic lung diseases.

Carmen Ramirez, whose father died of Legionnaires', pauses in this 2015 file photo. The Bronx, and specifically the area around the Opera Hotel, was in the middle of the largest outbreak in New York City's history (Spencer Platt/Getty Images).

How can you prevent it?
Keep things sanitized. At this time, there’s not a pill or a vaccine or anything that you can take to protect yourself.


It was in 2015 when the veterans home residents died in Illinois, and about four-dozen more were sickened. But news about Legionnaires’ has been streaming in almost ever since.

A judge will soon decide whether Michigan’s health director will face trial in the Flint water crisis. Nick Lyon is charged with involuntary manslaughter. He’s accused of waiting too long to tell the public about a Legionnaires’ disease outbreak in the Flint area in 2014-15 when the city was using water from the Flint River. At least 12 people were killed and 79 in the region got sick, according to the state.

With information from the Associated Press.

About the Author: