Two patients have died at a hospital after contracting a fungal infection linked to pigeon droppings.

The individuals are thought have caught the airborne disease at the Queen Elizabeth University hospital in Glasgow after inhaling the fungus cryptococcus, typically found in soil and pigeon droppings.

NHS Greater Glasgow and Clyde (NHSGGC), which runs the hospital, has launched an investigation into the outbreak. It said the likely source of the pigeon droppings was a non-public room, thought to contain machinery, which has now been cleaned.

NHSGGC said “control measures” had been introduced, which is understood to mean equipment to filter the air in some parts of the hospital, and that some patients, including children, who may be vulnerable to the disease have received medication, which was proving effective.

The health board said that the second patient who died was elderly and the death was due to an unrelated matter. It said it could not share further details of the case because of patient confidentiality.

Teresa Inkster, NHSGGC lead consultant for infection control, said: “Cryptococcus lives in the environment throughout the world. It rarely causes infection in humans. People can become infected with it after breathing in the microscopic fungi, although most people who are exposed to it never get sick from it.”

She said there had been no further cases since control measures were put in place. “We are continuing to monitor the air quality and these results are being analysed. It remains our priority to ensure a safe environment for patients and staff,” she added.

Portable air filters have been installed to help reassure “vulnerable patients”, NHSGGC said, adding that the organism is “harmless to the vast majority of people and rarely causes disease in humans”. A group of hospital patients are being moved within the hospital “due to their clinical diagnosis and ongoing treatment”.