NEW research has found a key human gene responsible for blocking most avian flu viruses from spilling over into people.
The latest international study into the pandemic potential of avian flu, which is led by scientists at the University of Glasgow, identified the human gene BTN3A3, which is commonly expressed in our airways, as a key human defence against such viruses.
Through a series of extensive tests, the study team were able to show that the BTN3A3 gene is vital to protecting humans against avian flu, as most strains of the virus cannot get past its defences.
Avian flu, also commonly referred to as bird flu, primarily spreads among wild birds such as ducks and gulls and can also infect farmed and domestic birds such as chickens, turkeys and quails.
Since 2022 there has been a rise in bird flu cases around the world in both domestic and wild birds.
While the disease mainly affects birds, it has been known to spill over into other species including, in rare cases, humans.
For example, the 1918 Spanish flu virus which caused more than 25 million deaths worldwide is believed to have originated from an avian strain.
However, experts agree there are still several gaps in our scientific knowledge that make it difficult to be able to predict which variant of avian influenza virus might spill over into the human population and when.
The team behind this study compared the behaviour of hundreds of genes normally expressed by human cells during a viral infection with either human seasonal viruses or avian flu viruses.
The study showed that the BTN3A3 gene was able to block the replication of avian flu in human cells, while the seasonal human flu viruses were resistant to BTN3A3.
The team also looked at avian flu viruses that occasionally do infect humans, for example H7N9, which has a mutation that allows them to ‘escape’ the blocking effects of the BTN3A3 gene.
Professor Massimo Palmarini, who led the study, said: “We know that most emerging viruses with human pandemic potential come from animals.
“It is therefore critical to understand which genetic barriers might block an animal virus from replicating in human cells, thereby preventing infection.
“Of course, viruses are constantly changing and can potentially overcome some of these barriers by mutating over time.
“This is why virus genetic surveillance will be crucial to help us better understand and control the spread of viruses with zoonotic and pandemic potential.”
The study, BTN3A3 evasion promotes the zoonotic potential of influenza A viruses, is published in Nature.
