Further genetic changes could lead to full immunity.

Researchers have used gene editing to create chickens with significant resistance to avian influenza.

The alteration to their DNA did not fully protect the birds from the virus, but the scientists have identified further genes which could be edited to possibly provide complete immunity.

The research could pave the way for the long-term protection of chickens from avian influenza.

The team, which included scientists from the Roslin Institute and Imperial College London, altered the protein ANP32A, a protein which avian influenza viruses use to help replicate themselves.

When the chickens which had been gene edited were exposed to a moderate dose of the H9N2-UDL strain of avian influenza, nine out of 10 of the birds did not become infected.

However when exposed to a high dose, five out of 10 birds became infected, but the amount of virus in the infected birds was much lower than the typical level.

There were no signs that the change in the birds’ DNA affected their health or wellbeing.

Looking at how the virus infected the gene-edited birds without using the ANP32A protein, the researchers discovered that it had instead used the two related proteins ANP32B and ANP32E.

The scientists found that making gene edits to all three proteins blocked the virus in cell cultures. No birds have yet been produced with the complete set of genetic changes.

Although the risk to UK poultry from avian influenza has now declined, according to the Government, between October 2021 and October 2022, 47.7m birds were culled in the UK and the EU.

Prof Mike McGrew of the Roslin Institute, one of the co-authors of the study, said: “Bird flu is a great threat to bird populations. Vaccination against the virus poses a number of challenges, with significant practical and cost issues associated with vaccine deployment.

“Gene-editing offers a promising route towards permanent disease resistance, which could be passed down through generations, protecting poultry and reducing the risks to humans and wild birds. Our work shows that stopping the spread of avian influenza in chickens will need several simultaneous genetic changes.”

Prof Wendy Barclay, of Imperial College London, and another of the study's co-authors, added: “Although we haven’t yet got the perfect combination of gene edits to take this approach into the field, the results have told us a lot about how influenza virus functions inside the infected cell and how to slow its replication.”

The study has been published in the journal Nature Communications.

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