A genetically modified ‘superchicken’ that doesn’t spread deadly bird flu has been developed by scientists. The bird is intended to prevent the outbreaks of avian influenza which lead to millions of birds being culled. It could also stop new strains of flu mutating in domestic fowl and spreading to people, leading to killer worldwide pandemics.
The British team behind the GM chicken say it is ‘inconceivable’ that its meat or eggs could be harmful. However, it will need rigorous safety checks before it could go into the food chain, they said.
But anti GM campaigners warned that genetic engineering was not the answer to stopping bird flu – and said the public would never accept GM eggs and meat.
Avian flu is a serious threat to farmers and people. Although it does not easily infect humans, when it does it can be deadly.
The latest, most virulent strain – called H5N1 – has killed more than 300 people since 2003 in 15 countries and led to the deaths of millions of birds. In 2007 around 260,000 turkeys were culled in East Anglia after outbreaks of H5N1.
Doctors fear it could mutate in flocks of chickens into a new strain that is transmissible from person to person, fuelling a pandemic that kills millions of people.
The GM chicken was created by a team at Cambridge University and Edinburgh University and reported today in the journal Science.
Dr Laurence Tiley, from Cambridge, said: ‘Preventing virus transmission in chickens should reduce the economic impact of the disease and reduce the risk posed to people exposed to the infected birds.’
The chickens carry an extra gene that stops the flu virus replicating in their bodies. The gene – which was added to embryo chicks while they were in the egg – produces ‘decoy’ loops of RNA, the chemical cousin of DN, in cells throughout their bodies.
The decoy RNA interferes with the machinery that viruses use to make copies of themselves inside cells and spread throughout the body.
So although GM chickens fall ill and die from flu – they cannot pass it onto other birds or people.
In tests at the Veterinary Laboratories Agency in Weybridge, Surrey, infecte GM chickens fell sick but did not transmit the flu virus to normal birds kept in the same pen.
The gene is expected to work against all strains of bird flu, and the virus cannot easily evolve to escape its effects.
Because the new gene is dominant, chicks bred from a pair of GM birds will also be unable to transmit bird flu. The trait will be passed down to future generations.
Dr Tiley said there was ‘no observable difference’ between the GM birds and their non-GM relatives he said.
‘The nature of the decoy molecule means it is pretty well inconceivable that could have any detrimental effect on somebody that ate it because RNA is an unstable molecule that is easily broken down by the gut,’ he said. ‘There is no reason to suggest that these chickens would be unsafe in any way.’
GM birds would need thorough safety tests and the approval of food agencies in America and Europe before they could enter the food chain.
Co-author Prof Helen Sang, from the Roslin Institute, Edinburgh, said: ‘Countries like China are interested in possibly of using GM to protect their poultry stocks and it will inevitably be more expensive because you will have to use products of breeding companies to stock your producers,’ she said.
However, costs would come down over time, she added.
The researchers are now working on chickens that are completely immune to bird flu.
They believe the technique could be used to protect against the spread of disease in other animals such as turkeys, geese and pigs.
But Pete Riley from GM Freeze said: ‘These are global industries with thousands of broiler and battery units around the world and it improbable that the GM chickens will be bred fast enough to keep pace with the mutations that are occurring in avian flu virus all the time around in the northern and southern hemisphere.
‘In intensive units the environment is quite different to the lab and so far this has not been part of the research. In addition, many poorer producers may find the additional cost of the GM birds too high and stick with conventionally bred birds.
‘Genetic diversity in chickens, not genetic modification of a single breed, is important in reducing the spread of infections, as it is with all farm animals’.