The Centre for Health Protection is investigating two cases of Legionnaires' disease affecting two men.
The first patient, aged 56, fell ill on July 27 and was admitted to United Christian Hospital yesterday. He is in a stable condition.
The second patient, aged 65, fell ill on August 1 and was admitted to Caritas Medical Centre's intensive care unit today. He is in a critical condition.
Both tested positive for Legionnaires' disease and had no recent travel history.
They are the 27th and 28th cases recorded this year.
