The Centre for Health Protection is investigating a case of Legionnaires' disease affecting a 79-year-old man.
He fell ill on August 11 and was admitted to Ruttonjee Hospital on August 14.
The clinical diagnosis is pneumonia and he is in stable condition.
He tested positive for Legionella pneumophila.
The patient has no recent travel history.
It is the 34th case recorded this year.
