Final answer:
Legionnaires' disease is caused by the bacterium Legionella pneumophila and is contracted by inhaling aerosols from contaminated water systems such as air conditioning cooling towers and humidifiers. This disease commonly affects individuals with compromised health, particularly involving the heart or lungs, and is not transmitted person to person. Legionellosis is often linked to poorly maintained water systems in buildings.
Step-by-step explanation:
The most accurate response to the client who has been diagnosed with Legionnaires' disease and is inquiring about how they contracted the illness would be to explain that legionellosis is caused by the bacterium Legionella pneumophila. This bacterium typically resides in moist environments and can be found in man-made water systems such as air-conditioning cooling towers, humidifiers, and fountains. People get infected when they inhale aerosols or mist containing the bacteria from these water sources. Particularly, individuals with pre-existing health conditions or weakened immune systems are more susceptible to such infections. Furthermore, it is important for the client to understand that Legionnaires' disease does not spread from person to person, but through inhalation of contaminated water droplets. Cases of Legionnaires' disease have been associated with complex water systems in buildings, including those found in large plumbing networks, air conditioning systems, and even decorative fountains, all of which can produce the necessary aerosols for transmission. Healthcare professionals have gathered evidence linking outbreaks to poorly maintained water systems where the bacteria can grow and spread.