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What are the common risk factors for Legionnaires’ disease? The most common risk factor is heavy cigarette smoking. However, chronic lung disease is also common. The most intense risk factor is organ transplantation; the medicines used to protect the new organ also compromise the patient’ defense system against infection. Patients who take corticosteroid medicines are Read More …

How is Legionnaires’ disease diagnosed? Specialized laboratory tests are necessary and, unfortunately, may not be available in many hospitals. These include culture on specialized Legionella media. Culture media furnish nutrients for the bacterium. When sputum from the patients is placed onto the culture media, the bacterium grows on the medium and can be identified.   Other Read More …

How do people contract Legionella? The most popular theory is that the organism is aerosolized in water and people inhale the droplets containing Legionella. However, new evidence suggests that another way of contracting Legionella is more common. “Aspiration” is the most common way that bacteria enter into the lungs to cause pneumonia. Aspiration means choking such Read More …

Is Legionnaires’ disease contagious? Legionnaires’ disease is not contagious. No special precautions are necessary. The disease is transmitted via drinking water, not by infected persons. (So it differs from SARS and influenza where masks must be worn). Likewise, women who are pregnant and their fetuses have nothing to fear from patients with Legionnaires’ disease.

Where do Legionella bacteria come from? Legionella are natural inhabitants of water and can be detected in rivers, lakes, and streams. One type of Legionella species (L. longbeachae) has been found in potting soil.

What is the prognosis and outcome for patients who have contracted Legionnaires’ disease? If the patient is treated with appropriate antibiotics near the onset of pneumonia, the outcome is excellent, especially if the patient has no underlying illness that compromises his/her immune system. For patients whose immune systems are compromised, including transplant recipients, delay of Read More …

What are the symptoms of Legionnaires’ disease? The incubation period of Legionnaires’ disease is from two to ten days; this is the time it takes before symptoms of the illness appear after being exposed to the bacteria. For several days, the patient may feel tired and weak. Most patients who are admitted to the hospital Read More …

How is Legionnaires’ disease treated? Many antibiotics are highly effective against Legionella bacteria. The two most potent classes of antibiotic are the macrolides (azithromycin), and the quinolones (ciprofloxacin, levofloxacin, moxifloxacin, gemifloxacin, trovofloxacin). Other agents that have been shown to be effective include tetracycline, doxycycline, minocycline, and trimethoprim/sulfamethoxazole.   Erythromycin, the former antibiotic of choice, has Read More …

What have been the water sources for Legionnaires’ disease? The major source is water distribution systems of large buildings, including hotels and hospitals. Cooling towers have long been thought to be a major source for Legionella, but new data suggest that this is an overemphasized mode of transmission. Other sources include mist machines, humidifiers, whirlpool Read More …

Patients, Family and Friends General Questions Ask The Experts Ask The Experts Name Name is mandatory Email Email is mandatory Confirm Email Confirm Email is mandatory How was the diagnosis of Legionnaires’ disease made? Please check any of the following: Blood tests for antibodiesUrine antigenDon’t knowIsolation of the Legionella bacterium by cultureSpecial stain: DFA. Does Read More …