As the UK Covid inquiry considers how well the country planned for and responded to the coronavirus pandemic which swept the globe in 2020, scientists are looking for clues that could help us spot future viral threats.
One of the likeliest avenues will be a zoonotic "spillover" event, where a virus jumps from animals into humans.
This does not necessarily mean that the virus can then spread from human-to-human, but several previous human pandemics have originated in animals such birds, bats, camels and pigs.
Researchers in Glasgow have now identified a gene that could play an important role in viral surveillance.
READ MORE: Glasgow scientists discover genetic clue to stopping spread of bird flu
What have we learned?
Scientists at Glasgow University's Centre for Virus (CVR) have identified the human gene, BTN3A3, as playing a key role in protecting humans against avian flu.
Although it is not the only gene involved in coding for an immune defence against strains of bird flu, it is the first time that the role of BTN3A3 has been identified.
Through a series of tests, the study team were able to show that the BTN3A3 gene blocks the replication of avian flu in human cells in the respiratory tract.
What about 'spillover' events?
The scientists wanted to understand why some humans do become infected with strains of 'bird flu'.
They discovered that some strains of avian flu viruses have developed mutations which enable them to 'escape' the blocking effects of BTN3A3.
This includes the H7N9 strain, which has infected more than 1,500 people since 2013 with a case-fatality rate of 40%.
The team analysed avian-isolated H7N9 sequences deposited at the Global Initiative on Sharing All Influenza Data (GISAID).
Before 2013, they found that only 14% (seven out of 50 samples) carried BTN3A3-resistant mutations. From 2013 onwards, however, this rose to 93.5%.
Analysis of isolates of the H5N1 strain which is currently in circulation and responsible for millions of birds' deaths shows that around 50% of samples are BTN3A3-resistant.
READ MORE: Devi Sridhar - Yes, Sweden has lockdown lessons for us
Why is this important?
At the moment there is no evidence of human-to-human transmission of H5N1 infections.
However, past pandemics show us that the first step is when viruses find a way to leap from animals into humans.
The original SARS (Severe acute respiratory syndrome) outbreak in 2002 was traced to a colony of bats, while MERS (Middle East respiratory syndrome) is believed to have spread to humans from camels.
Scientists want to use genomic surveillance to identify potential threats at an early stage.
That means they have to know which genes are involved in resistance, and which viral strains are displaying mutations that confer resistance.
READ MORE: The Spanish flu and Christmas in 1918
What about past pandemics?
By tracking past human influenza pandemics - including the devastating 1918-19 Spanish flu pandemic, thwe 1957 Asian flu, 1968 Hong Kong flu, and the 2009 swine flu pandemic - the researchers showed that they were all caused by influenza viruses that were resistant to BTN3A3.
This suggests that having resistance to this gene may be a key factor in whether any flu strain has human pandemic potential.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here