Two patients have died after contracting a fungal infection caused by pigeon droppings at the Queen Elizabeth University Hospital.
NHS Greater Glasgow and Clyde said an elderly patient died but from an unrelated cause.
Another infected patient has also died but the factors contributing to the death are still being investigated.
A non-public room, thought to contain machinery, was identified as a likely source. An investigation is under way.
NHSGGC confirmed a small number of vulnerable paediatric and adult patients are receiving medication to protect them against the airborne infection, which is a Cryptococcus species.