Researchers have successfully gene-edited chickens to enhance their resistance to bird flu, presenting a potential strategy for safeguarding poultry flocks against future outbreaks. Amid a severe avian flu outbreak since 2021, scientists at the University of Edinburgh explored the use of CRISPR technology to modify genes in chicken cells, specifically targeting the ANP32A protein used by all subtypes of the bird flu virus for replication.

The researchers altered two amino acids in ANP32A, preventing the virus from replicating in the edited chicken cells. Embryos were then gene-edited, resulting in ten chickens with the modified form of ANP32A. When exposed to the H9N2 subtype of bird flu, known for causing milder illness than H5N1, only one gene-edited chicken out of ten became infected, compared to all non-edited chickens.

Further testing with a viral dose 1000 times higher showed that 5 out of 10 gene-edited birds became infected, but with substantially lower virus levels in their airways compared to non-edited chickens. However, the virus developed genetic mutations in the gene-edited birds, allowing it to replicate with the assistance of proteins ANP32B and ANP32E.

The researchers proposed a comprehensive approach by editing genes for all three proteins together to achieve complete virus resistance in chicken cells. Despite these promising findings, significant barriers, including extensive testing, breeding, and distribution, must be overcome before gene-edited chickens become a reality. The researchers estimate it could take around 20 years before bird flu-resistant chickens are available for commercial farming.

While the technology offers potential solutions to avian influenza, considerations of health, welfare, and cultural acceptance must be addressed before widespread implementation. The study, conducted amid the ongoing global avian influenza crisis, suggests that a combination of genetic modification, extensive vaccination, and improved farming practices could be an effective strategy against bird flu.

By Impact Lab