Things you need to know about Legionnaires’ disease

Things you need to know about Legionnaires’ disease

Legionnaires’ disease (LD) is a severe form of pneumonia which is usually caused by Legionella bacteria. Its symptoms may include a high fever, muscle aches, chills, cough, headaches, and diarrhea.

The disease is not contagious between people.

So, you can’t catch it from person-to-person contact. Instead, most people get this disease from inhaling the bacteria. Smokers, older adults and people with compromised immune systems are mainly susceptible to Legionnaires’ disease.


The bacterium Legionella is responsible for Legionnaires’ disease. Outdoors, legionella bacteria survive in water and soil, but seldom cause infections.

Indoors, however, legionella bacteria can reproduce in almost all kinds of water systems like hot tubs, mist sprayers, and air conditioners and in grocery store produce departments.

Large, complex water systems, like those used by hospitals, hotels or large apartment buildings, maybe most susceptible to a spread of Legionnaires’ disease.

The places where the water system becomes contaminated by Legionella, showers and central air conditioning, could also expose you to the bacteria.

According to the Centers for Disease Control and Prevention (CDC), when Legionnaires’ is the most dangerous Legionnaires’ disease sends around 8,000 to 18,000 people in the United States to the hospital every year.

The death rate is approximately 10% overall. Unluckily, the hospital is one place where you are more likely to pick up the disorder, along with other health care services.

The spread of condition in health care settings is particularly problematic. This is because the elderly, people with weakened immune systems and people who already have conditions like diabetes and some cancers are at higher risk.

The CDC reports that the death rate is about 25% in these healthcare-related cases.


The common signs and symptoms of Legionnaires’ disease include cough, fever, and shortness of breath. Other signs could be body aches, headaches, diarrhea, nausea, and confusion. Generally, its symptoms take between two days and two weeks to develop. Nevertheless, not everybody exposed to the Legionella bacteria gets sick.

Most patients develop pneumonia in which some of the lungs’ air sacs fill with pus or fluid. Pneumonia might involve both of your lungs and become so severe that hospitalization is required.

Mental changes, like disorientation, confusion, hallucination, and loss of memory, can also occur to an extent which seems out of proportion to the seriousness of fever. Complete recovery can take quite a few weeks.


Although Legionnaires’ disease mainly affects the lungs, it rarely can cause infections in wounds and in other parts of your body, including the heart. Legionnaires’ disease can also cause a number of other life-threatening complications, counting;

  • Decreased pulmonary function
  • Fulminant respiratory failure
  • Septic shock, dehydration
  • Hyponatremia (because of a syndrome of inappropriate antidiuretic hormone (SIADH) secretion)
  • Respiratory insufficiency, hypoxic respiratory failure
  • Endocarditis
  • Neurologic symptoms; including headache, altered mental status, lethargy, and nonfocal neurologic examination findings
  • Gastrointestinal symptoms like diarrhea, vomiting
  • Renal failure
  • Rhabdomyolysis
  • Multiple organ failure
  • Coma
  • Bacteremia or abscess formation (in the lungs) in immunocompromised patients
  • Death; in 10% of treated nonimmunocompromised patients and in as many as 80% of untreated immunocompromised patients

Treatment for Legionnaires’ disease

Most of its cases are treated with oral antibiotics. More serious cases of Legionnaires’ disease might require hospitalization. Treatment in the hospital may include;

  • Antibiotics directly into a vein
  • Oxygen through a face mask
  • A machine to help you breathe

When you start to get better you might be able to take antibiotics at home. Usually, antibiotic treatment lasts 1 to 3 weeks.

Most healthy people make a full recovery, but it might take some weeks to feel back to normal. When not treated promptly and effectively, Legionnaires’ disease may be deadly, particularly if your immune system is weakened by medications or disease.




The author is a Medical Microbiologist and healthcare writer. She is a post-graduate of Medical Microbiology and Immunology. She covers all content on health and wellness including weight loss, nutrition, and general health. Twitter @Areeba94789300

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