legionnaires' disease

US /ˌliː.dʒəˈnerz dɪˌziːz/
UK /ˌliː.dʒəˈnerz dɪˌziːz/
"legionnaires' disease" picture
1.

a severe form of pneumonia caused by the bacterium Legionella pneumophila, typically spread by water droplets from air conditioning units or other water systems.

:
Several guests at the hotel contracted Legionnaires' disease from the contaminated water system.
Public health officials are investigating a potential outbreak of Legionnaires' disease.