Legionellosis is caused by the bacterium Legionella pneumophila and includes pneumonic form (Legionaires disease) and the non-pneumonic form (Pontiac Fever). Legionaires disease presents as pneumonia, with a dry non-productive cough and severe flu-like symptoms. It can occur sporadically as an uncommon cause of community-acquired pneumonia, or as cases associated with environmental sources such as hospitals, hotels and factories.
Further information on legionnaires disease see the health protection surveillance.
Public Health England: Legionnaires' disease: guidance, data and analysis