This disease is a serious form of pneumonia that happens when people get Legionella bacteria, which infect the lungs. While the most common symptoms include high fever, diarrhea, confusion, and cough, it may also cause other symptoms. People usually get this bacterium from water or cooling systems in large buildings (including hospitals, hotels, and others). Without immediate treatment, this condition can be life-threatening.
Furthermore, the bacterium that causes this type of pneumonia may also negatively affect the brain and gastrointestinal tract. Most people who are infected with this bacterium receive treatment in the hospital, and some of them may have chronic (long-lasting) complications even after recovering from this infection. In addition, Legionella may also cause another serious illness called Pontiac fever. It often causes symptoms similar to those of the flu.
Generally, this bacterial infection affects about 10,000 people in the U.S. each year.
Symptoms
People who are infected with Legionella experience symptoms within 14 days after exposure. Check some examples below:
- Dry cough (sometimes with blood)
- Diarrhea
- Headaches
- Nausea
- Vomiting
- Confusion
- Abdominal (belly) pain
- Fever
- Dyspnea (shortness of breath)
If any of the previous symptoms occur, immediately contact your healthcare professional.
Causes and Risk Factors
This infection occurs due to a bacterium called Legionella. In general, there are more than 60 species of this bacterium, but Legionnaires’ disease happens due to a type called Legionella penumophila. It can be found naturally in lakes, soil, and streams, but sometimes it can contaminate drinking water and air systems.
People often develop this infection when breathing in mist contaminated with bacteria or drinking contaminated water. Sometimes, water in the mouth may enter the lungs (aspiration). It usually occurs from:
- Faucets
- Humidifiers
- Shower heads
- Hot tubs
- Dirt
- Decorative water features (including fountains)
- Intubation during surgery
- Heating and cooling systems
It is important to know that if you ingest this bacterium, Legionnaires’ disease does not occur, but it may negatively affect your gastrointestinal tract. Furthermore, this bacterium is not contagious, which means it does not spread from one person to another.
While anyone can develop this type of pneumonia, some factors could elevate your risk. Check some examples below:
- Live in a long-term care facility
- Recently stayed in the hospital
- Weakened immune system
- Smoking
- Age – People who are over 50 years old are more likely to develop Legionnaires’ disease.
- Organ transplant
- Chronic (long-term) respiratory disorders, such as COPD (chronic obstructive pulmonary disease)
What Are The Long-term Effects of Legionnaires’ Disease?
People who develop this infection may also experience some complications, especially if they leave it untreated. Some examples are listed below:
- ARDS (acute respiratory distress syndrome) – This is a severe complication that may cause lung failure without immediate treatment.
- Rhabdomyolysis – Quick muscle breakdown may cause kidney damage.
- Septic shock – This complication causes a sudden and quick drop in blood pressure, which negatively affects blood flow to multiple tissues and organs in the body.
- Acute kidney failure – In such cases, the kidneys suddenly fail to filter waste from the blood. Without immediate dialysis, it may lead to kidney failure and eventually death.
- Respiratory failure – When the lungs cannot supply enough oxygen to the body or remove carbon dioxide, people need mechanical ventilation.
- Multiorgan failure – This is a serious complication in which the infections spread to other parts of the body. It may also lead to endocarditis (inflammation of the heart muscle), neurological problems (including confusion and ataxia), and others.
Furthermore, some people may experience complications even after recovery. Check some examples below:
- Neuromuscular fatigue
- Post-traumatic stress disorder (PTSD)
- Extreme fatigue
- Neurological symptoms (including difficulty concentrating, weakness, muscle aches, and others)
The previous list does not contain a full list of complications, but you can consult with your healthcare professional about preventive measures.
How to Prevent Legionnaires’ Disease?
There are some ways to reduce the risk of getting Legionella by maintaining and disinfecting water and ventilation systems. At home, you should make sure that faucets, shower heads, hot tubs, and humidifiers are properly cleaned and run regularly. Avoid plain water in place of windshield wiper fluid in the car.
Diagnosis
Physicians usually start the diagnosis of Legionnaires’ disease with a physical examination and questions about your medical history and symptoms. They may also ask about any recent travel to get more information about your disease. In any case, to confirm or rule out this infection, doctors perform the following tests and procedures. Examples include:
- Imaging tests – The following tests are often done to get images of the respiratory system (including the lungs). For example, CT (computerized tomography) scans, X-rays, and MRI (magnetic resonance imaging) scans.
- Urine and sputum tests
- Blood tests – These tests are used to check for Legionella in the blood. They may also help your physician understand how your organs are working.
- Bronchoscopy – During this procedure, doctors will look inside the lungs by using a small and flexible tube to check for Legionella.
- Thoracentesis – This test involves draining fluid from the outside of the lungs to check for the bacterium that causes this infection.
Treatment
Most of the time, this infection is treated with antibiotics. While some people get oral medicines, others may need IV (intravenous) antibiotics. Usually, doctors prescribe Azithromycin, Levofloxacin, Rifampin, Tetracycline, Doxycycline, Minocycline, Ciprofloxacin, or Moxifloxacin. Furthermore, if you experience moderate to severe breathing problems, you may need additional oxygen, which requires staying in the hospital during treatment.
Frequently Asked Questions
When should I see my healthcare provider?
Generally, you should visit a doctor if any of the following symptoms occur or if the treatment you take does not work. Check some symptoms below:
- High fever
- Trouble breathing
- Coughing up blood
- Neurological symptoms (including problems with balance or speech, or confusion)
Can you survive Legionnaires’ disease?
Despite it being a serious infection, most people survive with treatment. In general, the mortality (death) rate is approximately 10% in people who get treatment. People who ignore the symptoms and do not get treatment are more likely to die from Legionnaires’ disease.
What can be mistaken for Legionnaires’ disease?
Commonly, the following health conditions are mistaken for Legionnaires’ disease. These include respiratory syncytial virus (RSV), rhinovirus/enterovirus (R/E), human metapneumovirus (hMPV), human parainfluenza virus type 3 (HPIV-3), and adenovirus.
Can Legionnaires’ disease be prevented with a vaccine?
No, there is currently no vaccine available to prevent Legionnaires’ disease. The best way to reduce the risk is through proper maintenance and disinfection of water systems, including cooling towers, hot tubs, humidifiers, and plumbing systems.
How long does it take to recover from Legionnaires’ disease?
Recovery time varies depending on the severity of the infection and a person’s overall health. Some people recover within a few weeks, while others may experience fatigue, weakness, or difficulty concentrating for several months after the infection has cleared.
Can young and healthy people get Legionnaires’ disease?
Yes. Although adults over age 50, smokers, and people with weakened immune systems are at greater risk, healthy individuals can also develop Legionnaires’ disease if they are exposed to enough amount of Legionella bacteria.
Is Legionnaires’ disease seasonal?
This condition can occur at any time of the year, but they are often reported more frequently during the summer and early fall. Warmer temperatures can promote bacterial growth in certain water systems, increasing the risk of exposure.
What is the difference between Legionnaires’ disease and Pontiac fever?
Both illnesses are caused by Legionella bacteria. However, Legionnaires’ disease is a severe form of pneumonia that affects the lungs, while Pontiac fever is a milder illness that resembles the flu and does not cause pneumonia. Most people with Pontiac fever recover without specific treatment.
Can Legionnaires’ disease come back after treatment?
A recurrence is uncommon if the infection is properly treated. However, a person can become infected again if they are exposed to Legionella bacteria in the future, especially if they have underlying health conditions that increase their risk.
How common are Legionella outbreaks?
Most cases occur sporadically, but outbreaks can happen when a contaminated water system exposes multiple people. Outbreaks are often associated with large buildings such as hotels, hospitals, nursing homes, cruise ships, and office complexes, where complex water systems allow the bacteria to multiply. Ask your healthcare provider if you have additional questions.
