What are the first signs of Legionnaires' disease?

Author: Reinhold McCullough  |  Last update: Sunday, October 12, 2025

Legionnaires' disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days has been recorded in some outbreaks). Initially, symptoms are fever, loss of appetite, headache, malaise and lethargy. Some patients may also have muscle pain, diarrhoea and confusion.

Does Legionnaires disease go away by itself?

The legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Pontiac fever usually clears on its own, but untreated Legionnaires' disease can be fatal. Although prompt treatment with antibiotics usually cures Legionnaires' disease, some people continue to have problems after treatment.

How easy is it to catch Legionnaires?

How you get Legionnaires' disease. You can get Legionnaires' disease if you breathe in tiny droplets of water containing bacteria that cause the infection. It's usually caught in places like hotels, hospitals or offices where the bacteria have got into the water supply. It's less common to catch it at home.

How do I know if I have legionnaires?

Legionnaires' disease is a serious type of pneumonia you get when Legionella bacteria infect your lungs. Symptoms include high fever, cough, diarrhea and confusion. You can get Legionnaires' disease from water or cooling systems in large buildings, like hospitals or hotels.

Can you test for Legionnaires disease yourself?

Our innovative LegionellaFast is an immediate, on-site self-test developed to give a simple yes:no result for legionella. The simple test can be used anywhere, without the need for specialist expertise or equipment to carry out or interpret the test and its results.

Legionnaires’ Disease | Causes, Pathophysiology, Symptoms, Diagnosis, Treatment

How to get rid of Legionella?

Recirculate hot water continuously, if possible. Cold water: Store and circulate cold water at temperatures below the favorable range for Legionella (77–113°F, 25–45°C). Legionella may grow at temperatures as low as 68°F (20°C). Flushing: Flush low-flow piping runs and dead legs at least weekly.

What is the rapid test for Legionella?

LegionellaFast is an innovative rapid legionella test that needs no laboratory and is designed to give accurate in-field test results in only 25 minutes. It is the fastest legionella testing method commercially available on the market today.

What is the life expectancy of someone with Legionnaires' disease?

About 1 out of every 10 people who gets sick with Legionnaires' disease will die due to complications from their illness. For those who get Legionnaires' disease during a stay in a healthcare facility, about 1 out of every 4 will die.

Does Legionella smell?

A: No, water contaminated with Legionella bacteria does not typically have a distinctive smell or taste.

What is the drug of choice for Legionnaires disease?

Levofloxacin or azithromycin for 7–10 days is recommended in cases of moderate to severe Legionella pneumonia. For immunocompromised hosts, a 21-day course of levofloxacin or a 10-day course of azithromycin is usually recommended [105–107].

What time of year is Legionnaires disease most likely?

More illness is usually found in the summer and early fall, but it can happen any time of year.

What is the difference between Legionella and legionnaires' disease?

Legionella bacteria can cause a severe type of pneumonia (Legionnaires' disease) and mild flu-like illness (Pontiac fever).

How often should you run a shower to prevent Legionella?

When you first move into your home, run the bath and hand basin taps continuously for at least five minutes. This will flush through any bacteria. If your shower has not been used for a week or more, run water from both hot and cold supplies through the shower hose and showerhead for two minutes.

How do doctors test for legionnaires?

To diagnose Legionnaires' disease among other types of pneumonia, your doctor may order urine tests and a sputum culture to determine the presence of the Legionella bacteria.

What is similar to Legionnaires disease?

Pontiac fever is milder than Legionnaires' disease and presents with fever, headache, or muscle aches, but no signs of pneumonia. Pontiac fever can affect healthy people as well as those with underlying illnesses, and symptoms occur within 72 hours of exposure.

Is Legionella in tap water?

Legionella are relatively resistant to standard water disinfection procedures and, can occur in potable water. These bacteria have been found in water distribution systems of hospitals, hotels, clubs, public buildings, homes, and factories.

How do you flush out Legionella?

Whenever a property is to be left unused for a time, weekly flushing is a good way to reduce the chances of any problems cropping up. It is easy to do and requires only a small amount of time. Each tap and water outlet (including showers) should be opened and left to run through for at least five minutes.

What are three key symptoms of Legionnaires disease?

Legionnaires' disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days has been recorded in some outbreaks). Initially, symptoms are fever, loss of appetite, headache, malaise and lethargy. Some patients may also have muscle pain, diarrhoea and confusion.

How to test for Legionella at home?

4 Simple Steps
  1. Step 1 - Order Testing Kit. Your Legionella Testing Kit will include water sample bottle(s), easy to follow instructions and a FREE return package.
  2. Step 2 - Fill Sample Bottle. Fill the water sample bottle(s) from your taps following the instructions.
  3. Step 3 - Return Delivery. ...
  4. Step 4 - Get your Results.

In what season does Legionnaires disease occur?

Legionnaires'; disease is a serious condition with a 10-percent death rate. Illnesses usually occur in the summer and early fall, but Legionnaires' disease can happen in any season. Legionnaires' disease is not contagious.

Can you get Legionnaires' disease from air conditioning?

Back onto the big question: essentially, no. As we noted above, the Legionella Pneumophila bacteria breeds in water, not air conditioning vents. That means if you're worried about the possibility of Legionnaires' Disease then to be honest, your air conditioning system isn't the first place you should look!

What are the common sources of Legionella?

The most common sources of Legionella are in man-made water systems including, hot and cold water systems, cooling towers and spa pools. There are various systems available to supply hot and cold water services to premises and outdoor work facilities.

Can blood test detect Legionella?

Legionella tests look for these bacteria in urine or sputum. A blood test may be done to check if you have been exposed to the bacteria, but it cannot diagnose a Legionella infection. Legionnaires' disease has similar symptoms to some types of pneumonia, but it can also cause diarrhea and confusion.

What antibiotics are used to treat Legionella?

Mild Legionnaires disease can be treated with a single oral antibiotic regimen that has activity against Legionella pneumophila including fluroquinolones such as levofloxacin, and moxifloxacin, macrolides like azithromycin, clarithromycin. Other tetracyclines like doxycycline can also be used as an alternative therapy.

Is Legionella contagious?

Legionellosis is not contagious, meaning it is not spread from person-to-person. Disease transmission primarily occurs through inhaling Legionella-contaminated, aerosolized water. While rare, exposure is also possible from breathing in (i.e., aspirating) Legionella contaminated soil or while drinking water.

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