Legionnaires' Disease

1 What is Legionnaires' Disease?

Legionnaires' disease is a type of serious lung inflammation (pneumonia) caused by a bacterium known as Legionella. The disease is not communicable and mainly occurs when people accidently inhale the bacteria.


Legionnaires' disease easily affects people with weak immune systems, older adults, and smokers. The infectious agent of Legionnaires’ disease is also responsible for causing a milder illness called Pontiac fever.

Separately or together, the two illnesses are sometimes called legionellosis. Pontiac fever usually not require treatment but untreated Legionnaires' disease can be fatal.

Although the cure of Legionnaires' disease is possible with antibiotics when treated at an initial stage, but there are cases where a person may experience problems even after treatment.

2 Symptoms

Legionnaires' disease usually develops within 2 to 10 days after exposure to Legionella bacteria and it frequently begins with the following signs and symptoms:

  • Headache
  • Muscle pain
  • Chills and fever that may be 104 F (40 C) or higher

By the second or third day, other signs and symptoms are developed that may include:

Although Legionnaires' disease primarily affects the lungs, it can occasionally cause infections in the wounds and other parts of the body, including the heart.

A mild form of Legionnaires' disease — known as Pontiac fever — may produce signs and symptoms including fever, chills, headache and muscle aches.

Pontiac fever doesn't infect your lungs, and symptoms usually clear within two to five days.

See your doctor if you think you've been exposed to Legionella bacteria.

Diagnosing and treating Legionnaires' disease as soon as possible and can help shorten the recovery period and preventing serious complications. For people at high risk, prompt treatment is critical.

3 Causes

Legionella is the causal agent of Legionnaires' disease. Legionella easily thrives in soil, hot tubs, swimming pools, cooling systems or air-conditioning units for large buildings, such as hospitals and natural water bodies, such as lake or rivers.

The warm and moist environment in such places is optimal for the growth and spread of the bacteria.

Although the bacteria primarily spread through aerosolized water droplets, the infection can be transmitted by other routes, including:

  • Aspiration: This occurs when liquids accidentally enter your lungs, usually because you cough or choke while drinking. If you aspirate water containing Legionella bacteria, you may develop Legionnaires' disease.
  • Soil: A few people have contracted Legionnaires' disease after working in the garden or using contaminated potting soil.

4 Making a Diagnosis

Making a diagnosis of Legionnaires' disease is done by performing several tests.

You're likely to start by seeing your family doctor or a primary care provider. However, in some cases, you may be referred to a doctor who specializes in treating lung disease (pulmonologist) or infectious diseases, or you may be advised to go to an emergency department.

Your doctor will ask you a number of questions so keep details of all signs and symptoms and other important information.

The doctor is most likely to ask:

  • When did you begin experiencing symptoms?
  • Have your symptoms been continuous?
  • Have your symptoms been worsening since their onset?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?

To help identify the presence of Legionella bacteria quickly, your doctor may use a test that checks your urine for Legionella antigens — foreign substances that trigger an immune system response.

You may also have one or more of the following:

  • Blood tests
  • Chest X-ray, which doesn't confirm Legionnaires' disease but can show the extent of infection in your lungs
  • Tests on a sample of your sputum or lung tissue
  • A CT scan of your brain or a spinal tap (lumbar puncture) if you have neurological symptoms such as confusion or trouble concentrating

5 Treatment

The treatment of Legionnaires’ disease typically involves a 10 to 14-days course of intravenous (injected) antibiotics.

These may include one or combination of the following antibiotics:

  • The fluoroquinolones such as levofloxacin (Levaquin), and moxifloxacin (Avelox)
  • The macrolides such as erythromycin, azithromyocin (Zithromax), and clarithromycin (Biaxin)
  • The tetracyclines including doxycycline (Vibramycin) or
  • The Glycylcyclines

The choice of antibiotic is often dependent on the patient's clinical state, tolerance to the medication, and degree of certainty as to the diagnosis.

Zithromax and Levaquin are particularly effective because of decreased gastrointestinal irritation, higher potency, better penetration into tissue, and once-daily dosing.

This medication may cause nausea, dizziness, headaches, loss of appetite and chest pains. If the patient has weak immune system or chronic conditions, such as diabetes, serious lung infections or is very old, he/she may need to be hospitalized.

One crucial thing that your doctor will carefully consider is preventing from dehydration. Your doctor may also refer you to a specialist of treating lung diseases or infectious diseases, if needed.

6 Prevention

To prevent Legionnaire's disease, the following points should be considered:

  • Proper maintenance, cleaning, and disinfection of water systems, pools, and spas
  • Avoid smoking. It is the most crucial thing you can do to lower your risk of infection.

7 Alternative and Homeopathic Remedies

Several alternative home remedies as described below can help you fight against the Legionnaires’ disease:

  • Drink more herbal tea like catnip, echinacea, and chamomile tea or anise seed tea.
  • Eating or chewing olive leaves, olive oil may also use.
  • Eating citrus and ginger.
  • Avoiding damp or wet locations.

8 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with Legionnaires' disease.

To prevent your condition from getting worse follow these steps:

  • Don't smoke or be around smoke.
  • Don't drink alcohol.
  • Stay out of work or school, and rest as much as you can.
  • Drink plenty of fluids.
  • If you get sicker before you see a doctor, go to an emergency room.

9 Risks and Complications

There are several risks and complications associated with Legionnaires' disease.

The factors which increase risks and complications of Legionnaires’ disease are described below.

  • Smoking: Smokers are at greater risk of getting the infection.
  • Age: People over 50 years of age are more prone to the infection.
  • Other disorders : Individuals with kidney disease, diabetes, cancer (especially lung cancer or leukemia), or certain lung condition, such as COPD (chronic obstructive pulmonary disease) are at greater risk of developing complications.

The patient may develop complications like:

  • Respiratory failure - the body does not get enough oxygen from the lungs to function properly.
  • Kidney failure - there can be a serious build-up of fluids and waste in the blood.
  • Septic shock - blood pressure can suddenly drop dramatically, reducing the blood supply to vital organs, including the brain and kidneys. This is caused by the blood infection.