European scientists have found a way to genetically modify chickens so that they don't transmit bird flu, according to new research.
Credit: AFP/Tengku Bahar
SYDNEY: Genetically modified (GM) chickens that do not pass on avian influenza have been developed according to UK researchers, and could be used in the fight against the disease that affects both birds and humans.
Avian influenza (AI) is a disease present in both wild and domestic birds, and since 2003, the deadly H5N1 strain has claimed 306 human lives. Estimates suggest the cost to the poultry industry has been in excess of US$10 billion.
“This is an important step towards our goal of making chickens genetically resistant to AI virus,” said veterinary researcher Laurence Tiley of the University of Cambridge, a co-author of the study published in Science.
Potential pandemic
According to the World Health Organisation, the H5N1 strain of AI which can infect humans meets all the criteria to become a pandemic except for one – the ability to spread effectively between humans. The virus is transmitted to humans by close contact with infected birds or their excrement, and cannot be passed from human to human.
But there is concern that the virus could mutate to become a deadly pandemic strain. “Because chickens can transmit some AI strains to humans, they are a potential source for new pandemic strains,” said Tiley. “Eliminating AI from chickens would therefore block one possible route for new AI strains to emerge in people.”
Vaccinating chickens against AI is costly, and because influenza viruses mutate rapidly, vaccination has to be updated on a regular basis. It also doesn’t guarantee that the virus won’t spread through the flock.
Tricking the virus
Tiley and his colleagues have largely reduced the chances of the virus from transmitted from a GM chicken to any other chickens. What’s more, it should be effective against all strains of AI – including mutations yet to come.
Viruses reproduce using an enzyme known as RNA polymerase which copies the virus genome. The British scientists turned that system against the virus by modifying the DNA of the chickens so that in every cell they produced a small amount of ‘decoy’ RNA.
