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Legionnaires Disease: Causes, Symptoms and Treatment

Synopsis: Information regarding Legionnaires Disease including causes, symptoms, tests and treatment.1

Author: Disabled World Contact: Disabled World

Published: 2014-05-26

Main Digest

Legionnaire's disease is a form of severe pneumonia involving inflammation usually caused by a resulting infection. The disease is caused by a bacterium known as, 'legionalla.' People cannot catch Legionnaire's disease from person-to-person contact. Instead, the majority of people get the disease from inhaling the bacteria. Older adults, people with weakened immune systems, as well as smokers, are all especially susceptible to Legionnaire's disease.

The Legionella bacterium also causes, 'Pontiac fever,' which is a milder form of illness that resembles the flu. Separately or together, the two forms of illnesses are at times referred to as, 'legionellosis.' Pontiac fever often times clears on its own. Untreated Legionnaire's disease; however, may be fatal. While prompt treatment with antibiotics usually cures Legionnaire's disease, some people continue to experience issues even after receiving treatment.

The disease got its name as a result of an outbreak during the 1976 convention of the American Legion in the city of Philadelphia. Approximately 180 American Legion members who were attending the conference contracted a mysterious form of pneumonia that failed to respond to conventional antibiotic treatment; 29 of them died. Over time, the culprit turned out to be the Legionella pneumophila - a bacteria that was proliferating in the air conditioning system of the hotel.

Chart showing signs and symptoms of Legionnaires disease
Chart showing signs and symptoms of Legionnaires disease

Symptoms of Legionnaire's Disease

Legionnaire's disease commonly develops 2-10 days after a person is exposed to legionella bacteria. The disease frequently starts with signs and symptoms which include the following:

By the 2nd or 3rd day, a person with the disease will develop additional signs and symptoms. These signs and symptoms may include:

While Legionnaire's disease mainly affects a person's lungs, it occasionally may cause infections in wounds or other parts of a person's body, to include their heart. A mild form of Legionnaire's disease known as Pontiac Fever might cause signs and symptoms that include chills, fever, and muscle aches. Pontiac fever does not infect a person's lungs and the symptoms often times clear with 2-5 days.

Causes of Legionnaire's Disease

The bacterium, 'Legionella pneumophila,' is responsible for the majority of instances of Legionnaire's disease. Outside, legionella bacteria have the ability to survive in water and soil, yet rarely cause infections. Inside, legionella bacteria have the ability to multiply in all kinds of water system to include air conditioners, hot tubs and mist sprayers in grocery store produce departments. While it is possible to contract Legionnaire's disease from home plumbing systems, the majority of outbreaks have happened in larger buildings - maybe because complex systems permit the bacteria to grow and spread more easily.

Most people become infected when they breathe in microscopic water droplets that contain legionella bacteria. The water droplets may come from a faucet, shower, whirlpool, or water dispersed through the ventilation system of a large building. Outbreaks of the infection have been linked to a number of sources such as:

Legionella bacteria mainly spread through aerosolized water droplets. The infection can be transmitted in other ways; however, to include the following:

Soil: Some people have contracted Legionnaire's disease after they have worked in a garden, or used contaminated potting soil.

Aspiration: Aspiration happens when liquids accidentally enter a person's lungs, commonly because they cough or choke as they are drinking. If they aspirate water that contains legionella bacteria, they might develop Legionnaire's disease.

Risk factors for Legionnaire's Disease

The fact is - not everyone who is exposed to legionella bacteria becomes ill. A person is more likely to develop an infection if they:

A Person is More Likely to Develop an Infection if They:
Are over the age of 50.
Are a smoker - smoking damages a person's lungs and makes them more susceptible to all forms of lung infections.
Have a chronic lung disease such as emphysema, or another serious conditions such as kidney disease, cancer, or diabetes.
Have a weakened immune system as a result of HIV/AIDS, or certain medications; particularly corticosteroids and drugs taken to prevent organ rejection following a transplant.

Legionnaire's disease is a local and sporadic issue in nursing homes and hospitals where germs might spread easily and people are more vulnerable to infections.

Complications of Legionnaire's Disease

Legionnaire's disease may lead to several life-threatening complications. These complications may include the following:

Respiratory Failure: Respiratory failure happens when a person's lungs no longer have the ability to provide their body with enough oxygen, or cannot remove enough carbon dioxide from their blood.

Septic Shock: Septic shock occurs when a severe and sudden drop in a person's blood pressure reduces blood flow to their vital organs, particularly their brain and kidneys. The person's heart attempts to compensate by increasing the volume of blood that is pumped, yet the additional workload eventually weakens the person's heat and reduces blood flow even more.

Acute Kidney Failure: Acute kidney failure involves the sudden loss of a person's kidney's ability to perform their main function, which is filtering waste material from their blood. When a person's kidneys fail, dangerous levels of waste and fluid build up in their body.

If Legionnaire's disease is not treated quickly and effectively, it may be fatal. The potential for the disease to be fatal is particularly true if a person's immune system is weakened by medications or disease.

Tests and Diagnosis for Legionnaire's Disease

Legionnaire's disease is similar to other forms of pneumonia. To assist with identifying the presence of legionella bacteria quickly, a doctor might use a test that checks a person's urine for legionella antigens, which are foreign substances that trigger an immune system response. A person might also have 1 or more of the following tests or procedures:

Treatment and Medications for Legionnaire's Disease

Antibiotics are used to treat Legionnaire's disease, to be plain. The sooner antibiotic therapy is started, the less likely the chances are a person will experience serious complications or die. In a number of instances, treatment does require hospitalization. Pontiac fever goes away by itself without treatment and does not cause lingering issues.

Preventing Legionnaire's Disease

Outbreaks of Legionnaire's disease can be prevented, but prevention does require absolutely meticulous cleaning and disinfection of pools, spas and water systems. Avoiding smoking is the #1 most important thing a person can do to decrease their risk of becoming infected. Smoking increases the chances that a person will develop Legionnaire's disease if they are exposed to legionella bacteria.

Legionella (Legionnaires' Disease and Pontiac Fever)

Pontiac fever and Legionnaires' disease may also be called "legionellosis" (LEE-juh-nuh-low-sis) separately or together. Legionellosis is a term for any disease caused by Legionella bacteria.

What is Legionnaires' disease

Legionnaires' disease is a common name for one of the several illnesses caused by Legionnaires' disease bacteria (LDB). Legionnaires' disease is an infection of the lungs and is a form of pneumonia. More than 43 species of Legionella have been identified and more than 20 linked with human diseases.

Legionnaires' Disease

Legionnaires' Disease is recognized as an acute respiratory pneumonia caused by the aerobic gram-negative microorganism, Legionella pneumophila, and other species. This microorganism may also affect other body systems. Afflicted patients may have pulmonary (lung and bronchi), gastrointestinal tract, and central nervous system complications.

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Cite Page: Journal: Disabled World. Language: English (U.S.). Author: Disabled World. Electronic Publication Date: 2014-05-26. Last Revised Date: 2014-05-26. Reference Title: Legionnaires Disease: Causes, Symptoms and Treatment, Source: <a href=>Legionnaires Disease: Causes, Symptoms and Treatment</a>. Abstract: Information regarding Legionnaires Disease including causes, symptoms, tests and treatment. Retrieved 2021-02-28, from - Reference Category Number: DW#76-10347.