A LONG-AWAITED probe into the deaths of two cancer patients who contracted a fungal infection during treatment at Glasgow’s new superhospital has ruled out any link to pigeon droppings contaminating the ventilation system.

Investigators told The Herald that it remains unclear how the 10-year-old boy and 73-year-old woman picked up the bug, Cryptococcus neoformans, which is widespread in the environment and commonly found in bird excrement.

It is harmless to most people, but potentially deadly for those with weakened immune responses.

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The boy, who has never been named, was being treated for leukaemia at the £842 million Queen Elizabeth University Hospital in Glasgow, when he died in December 2018. A subsequent post-mortem detected Cryptococcus.

The woman, later named as Gail Armstrong, had also tested positive for the fungus and died in January 2019.

Today, investigators stressed that the particular strain of Cryptococcus which affected both patients is not typical to pigeons.

In their independent review, Dr Andrew Fraser and Dr Brian Montgomery, also said computer simulations had discounted the theory that air movement around the QEUH’s helipad could have “propelled pathogens into the ventilation system”, and that it was “improbable” fungal spores could have travelled via air shafts from plant rooms where pigeons were found and then been inhaled by the patients.

“The locations of bird sightings and infection sites are too far apart with too many physical barriers between them to realistically link the two,” they wrote.

Pigeon remains and excrement were found close to one air inlet, they said, but this was not supplying ventilation to the part of the hospital where both spent most of their time as inpatients.

They concluded: “In the case of the two people with Cryptococcus infection, there is not a sound evidential basis on which to make a link between their infection, subsequent deaths, and the presence or proximity of pigeons or their excrement.”

Speaking to The Herald, Dr Montgomery said: “The Cryptococcus that was identified in Glasgow was actually a different species from the one that is commonly found in pigeons, which hasn’t actually really made it into the public conciousness yet.

“Another thing that’s quite telling is that Cryptococcus has also been found in other hospitals in the west of Scotland, but only became a problem at the Queen Elizabeth because of the patient population they were dealing with.”

The review found design and build of the QEUH was “consistent with a more conventional hospital”, rather than one treating severely immuno-compromised patients.

Dr Fraser said it was possible Cryptococcus had been carried into the hospital environment on someone’s clothes or skin, then spread to vulnerable patients.

“That’s a possible explanation,” he said. “Another one would be that patients don’t spend their entire time in hospital. Sometimes they get breaks and get out, and it’s lying around in the atmosphere pretty widely.”

The death of a third patient, 63-year-old Mito Kaur, was originally linked to a rare Mucor fungus but this has since been discounted.

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The review concluded that cancer patients had been “exposed to risk that could have been lower” due to flaws in the design and build of ventilation and water supply systems.

However, they said there was “no clear evidence” linking these failures to avoidable deaths, and that upgrades to water, drainage and ventilation systems have “[minimised] the risk of infection” to cancer patients.