The Centre for Health Protection is investigating a case of Legionnaires' disease affecting a 70-year-old man.
He fell ill on August 8. He went to Prince of Wales Hospital's Accident & Emergency Department today and was admitted to the intensive care unit.
The clinical diagnosis is pneumonia and he is in a serious condition.
He tested positive for Legionella pneumophila.
The patient had travelled to Guangdong during the incubation period and stayed in Hong Kong before falling ill.
His home contact has no symptoms.
