Global & Disaster Medicine

Archive for the ‘Legionnaire’s Disease’ Category

Lithuania: An emergency has been declared in the capital city of Vilnius after Legionella bacteria were found in the water systems of several apartment buildings.

Baltic Times

x-ray of chest



Legionellosis is bacterial respiratory disease caused by Legionella that can present as either Legionnaires’ disease or Pontiac fever. Legionnaires’ disease is a common cause of severe pneumonia requiring hospitalization, while Pontiac fever generally resolves on its own.

The following table summarizes key clinical differences between Legionnaires’ disease and Pontiac fever.

Legionnaires’ disease
Clinical features Pneumonia, cough, fever
Pathogenesis Replication of organism
Radiographic pneumonia Yes
Incubation period 2 to 10* days after exposure
Percent of persons who become ill,
when exposed to the source of an outbreak
Less than 5%
Isolation of organism Possible
Outcome Hospitalization common
Case-fatality rate: 10%, approximately 30% for healthcare-associated cases

Minnesota health officials have confirmed 3 new cases of Legionnaires’ disease linked to the ongoing Hopkins outbreak, bringing the total number to 20, including one death.


x-ray of chest

Fast Facts

  • Legionella can cause Legionnaires’ disease or Pontiac fever, collectively known as legionellosis.
  • The bacterium was named after an outbreak in 1976, when many people who went to a Philadelphia convention of the American Legion got sick with pneumonia (lung infection).
  • About 5,000 cases of Legionnaires’ disease are now reported each year in the United States. [1]
  • About one out of every 10 people who get sick from Legionnaires’ disease will die. [2]
  • People can get Legionnaires’ disease or Pontiac fever when they breathe in a mist (small droplets of water in the air) that has been contaminated with Legionella.
  • In general, Legionnaires’ disease is not spread from one person to another. However, this may be possible in rare cases. [2]
  • Legionella is found naturally in fresh water environments, like lakes and streams, but can become a health concern in human-made water systems.
  • Keeping Legionella out of water systems in buildings is key to preventing infection.


CDC: The number of people with Legionnaires’ disease grew by nearly 4 times from 2000–2014.


Legionnaires’ disease is deadly for about 10% of people who get it.

9 in 10. CDC investigations show almost all outbreaks were caused by problems preventable with more effective water management.

CDC investigated the first outbreak of Legionnaires’ disease, a serious lung infection (pneumonia), in 1976. An increasing number of people in the US are getting this disease, which is caused by breathing in small water droplets contaminated with Legionella germs. About 5,000 people are diagnosed with Legionnaires’ disease and there are at least 20 outbreaks reported each year. Most identified outbreaks are in buildings with large water systems, such as hotels, long-term care facilities, and hospitals. Legionella grows best in building water systems that are not well maintained. Building owners and managers should adopt newly published standards that promote Legionella water management programs, which are ways to reduce the risk of this germ in building water systems.

 Graphic: Legionnaires disease is on the rise

 Graphic: Legionella can grow and spread in many parts of a building



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