This micrograph depicted cytoarchitectural details seen in a lung tissue specimen from a Knoxville patient with fatal pneumonia due to Legionnaires’ disease. The tissue was stained using Dieterle’s silver stain, which employs a silver-impregnation staining technique, the results of which reveals the presence of Legionella pneumophila bacteria.
How serious is it? What is the treatment?
Legionnaires' disease can be very serious and can cause death in up to 5% to 30% of cases. Most cases can be treated successfully with antibiotics, and healthy people usually recover from infection.
Where do Legionella bacteria come from?
The Legionella bacteria are found naturally in the environment, usually in water, growing best in warm water, like the kind found in hot tubs, cooling towers, hot water tanks, large plumbing systems, or parts of the air-conditioning systems of large buildings. They do not seem to grow in car or window air-conditioners.What are the symptoms of Legionnaires’ disease?
Legionnaires' disease can have symptoms like many other forms of pneumonia, so it can be hard to diagnose at first. Signs of the disease can include: a high fever, chills, and a cough. Some people may also suffer from muscle aches and headaches. Chest X-rays are needed to find the pneumonia caused by the bacteria, and other tests can be done on sputum (phlegm), as well as blood or urine to find evidence of the bacteria in the body.
Symptoms usually begin 2-14 days after being exposed to the bacteria.
A milder infection caused by the same type of Legionella bacteria is called Pontiac Fever, symptoms of which usually last for 2-5 days and may also include fever, headaches, and muscle aches; however, there is no pneumonia. Symptoms resolve on their own without treatment and without causing further problems.
Pontiac Fever and Legionnaires’ disease may also be called “Legionellosis” separately or together.