This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Legionnaire disease causes? 
Select and explain. 
A. Respiratory disease, B. U.T.I, C. Retroperitoneal fibrosis, D. Acute gastroenteritis
A: Respiratory disease
Answer: A: Respiratory disease 
Explanation: Ref: Page 1138: Harrison 20th edition* The bacterium L. pneumophila leads to legionnaire disease.* The most common form of transmission of Legionella is inhalation of contaminated aerosols produced in conjunction with water sprays, jets or mists.* It has 2 distinct clinical syndromes: Legionnaires disease, which most often manifests as severe pneumonia accompanied by multisystemic disease, and Pontiac fever, which is an acute, febrile, self-limited, viral-like illness