2023-10-31 21:30:10
Genetically Modified Chickens for Bird Flu Resistance Pose Threat to Humans, Study Finds
British researchers recently reported in the journal Nature Communications that their attempts to genetically engineer laying hens to be resistant to a strain of bird flu have resulted in mutated viruses that could potentially pose a threat to humans. The study, conducted by scientists from Edinburgh’s Roslin Institute and Imperial College London, used the genetic engineering tool Crispr/Cas to modify the gene responsible for the production of a protein called ANP32A, which the bird flu virus uses to multiply.
The researchers found that the modified ANP32A protein, which contained two additional amino acids, prevented the viruses from reproducing in nine out of ten chickens when the viral load was low. However, when the viral load was increased 1,000-fold, half of the animals became ill. Some of the viruses had mutated and learned to use related proteins, ANP32B and ANP32E, to replicate. The researchers also discovered that these mutated viruses were able to multiply in human respiratory tract cells and use human ANP32 proteins.
While the study authors emphasized to journalists that the modified chickens produced in their experiments would never be used in agriculture, a risk of a pandemic emerged if the modified viruses continued to exist and spread in the real world. The reporter for the Neue Zürcher Zeitung, who is a molecular biologist, explained that if the modified viruses continued to mutate, there is a possibility that a pandemic virus could emerge, similar to the Spanish flu 100 years ago.
To mitigate the risk, the researchers created chickens that no longer produced ANP32A, but this only slightly limited the mutated viruses. In laboratory experiments, they also created chicken cells lacking all three ANP32 proteins, preventing replication of the original virus and its mutations. However, the researchers acknowledged that this combination of genetic modifications could be harmful to the animals’ health.
Timm Harder, a bird flu expert at the Friedrich Loeffler Institute for Animal Health, explained that according to European law, genetically engineered animals like these chickens would be classified as genetically modified organisms. Their use would require genetic engineering approval and could only be kept in a genetic engineering facility. Mass use would require adapting existing laws. Moreover, long-term experiments are needed to understand the effects of the switched-off genes on the chickens and their behavior against more aggressive avian influenza viruses, such as H5N1.
Virologist Stephan Ludwig from the University of Münster praised the study’s proof-of-concept in achieving robust resistance to infection through gene editing. However, he highlighted the viruses’ rapid adaptability, along with legal and ethical hurdles and acceptance issues, as barriers to the practical application of this research.
In conclusion, while the study demonstrates the potential for genetic engineering to confer resistance to bird flu, concerns about the mutated viruses’ impact on humans, as well as legal and ethical considerations, necessitate further research and careful evaluation before it can be put into practice.]
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