Legionellosis

Overview

Legionnaires' disease (LEE-juh-nares) is caused by a type of bacteria called Legionella. The bacteria got its name in 1976, when many people who went to a Philadelphia convention of the American Legion suffered from an outbreak of this disease, a type of pneumonia (lung infection). Although this type of bacteria was around before1976, more illness from Legionnaires' disease is being detected now. This is because we are now looking for this disease whenever a patient has pneumonia.

Symptoms

No symptoms - many people are not affected by the disease

  • Flu-like symptoms
  • Fever
  • Chills
  • Productive or non-productive cough
  • Abdominal pain
  • Diarrhea
  • Confusion
  • Muscle aches
  • Headache
  • Tiredness
  • Loss of appetite
  • Coughing
  • Confusion
  • Delirium
  • Pulmonary complications
  • Gastrointestinal tract complications
  • Central nervous system complications
  • Kidney insufficiency
  • Pneumonia
  • Headache
  • Muscle pain
  • High fever
  • Nausea
  • Vomiting
  • Diarrhea
  • Shaking chills
  • Dry cough
  • Chest pain
  • Pneumonia
  • Confusion
  • Disorientation
  • Headache
  • Aching muscles
  • Loss of appetite
  • Impaired coordination
  • Nausea
  • Vomiting
  • Fatigue
  • Fever
  • Chills
  • Malaise
  • Diarrhea
  • Confusion
  • Cough
  • Coughing up phlegm
  • Pneumonia
  • Impaired kidney function
  • Impaired liver function

Causes

The causative agents, legionellae, are freshwater bacteria that are found in aquatic environments worldwide but artificial water systems sometimes provide environments conducive to the growth of Legionella bacteria. These bacteria survive within or between the cells as parasites of free-living protozoa and within biofilms which develop in water systems where bacteria survive. They can cause human infections by infecting other human cells utilizing a similar mechanism to that used to infect protozoa. L. pneumophila is the species most frequently isolated from patients with either community, travel-associated or hospital-acquired legionellosis.

Prevention

There is no vaccine currently available for Legionnaires’ disease. Patients with the non-pneumonic form of infection do not require any antibiotic treatment and the symptomatic approach is sufficient. Patients with Legionnaires’ disease always require antibiotic treatment, following laboratory confirmation of diagnosis.