Flu free fowl

February 2011

The latest UK research on GM is the creation of flu-free chickens.  In these novel birds, the dreaded H5N1 virus can't replicate as normal, doesn't infect the rest of the flock, and therefore, presumably, won't transfer to humans.

Avian flu continues to be a global health concern.  Although primarily a disease of wild birds, it occasionally infects poultry flocks in which it can spread like wildfire.  Controls, such as vaccination and bio-security measures, are complicated by the nature of the virus which is not a single type of virus, but exists in many subtypes and, like all flu, is an ever-evolving “master of mutability”.

Fears of a major outbreak of the virus in the UK in 2006 came after a swan, found dead off the coast of Fife, was discovered to be infected with H5N1.  The virus did not cross any species barriers in Scotland and the feared pandemic did not happen.

According to World Health Organisation data, there have been a total of 306 deaths world-wide from H5N1 since 2003.

Clearly, there have not so far been a great number of fatalities, but scientists still fear that H5N1 in domestic fowl will create a bridge to the emergence of a human strain of the virus which could kill millions of people.

The new genetic trick to beat bird-flu doesn't use a gene as such, but uses DNA which generates a small 'RNA' mirror of itself.  The novel RNA interferes with the viral enzyme which the pathogen uses to replicate itself.  Infected birds still die, but the pathogen is unable to spread to others.

In a bid to thwart the viral evolution which would soon side-step a single blockage, a genetic eight-fold 'belts and braces' strategy has been employed: the novel RNA has been designed to target eight sites on the viral genome where the enzyme would normally bind and become active.  This multiple interference makes it necessary for the virus to change both its enzyme and all eight binding sites at the same time to evolve resistance to the anti-flu fowl.

Future plans include the insertion of more DNA belts and braces to achieve absolute control of the H5N1 plus two other viral threats (Newcastle and Marek's disease).

The time-scale for successful completion of this research is not clear, but one US commentator pointed out that the trade in both broiler and egg-laying chickens has become consolidated in a handful of companies which essentially determine what stocks are used by chicken farmers globally.  This means that transgenic chickens could theoretically replace non-transgenic breeds worldwide in a few years.  (GM Freeze' comment on this was that we need genetic diversity in our chickens, not genetic modification of a single breed.)

Announcing the initial success of the flu-free chicken project at the Oxford Farming Conference (see note below), one of the team acknowledged the obstacle of consumer acceptance.  His views on overcoming this hurdle were that policy makers would have to defeat the negative connotations associated with GM, and that
“We need a more radical regulation system which is not obsessed with the technology but with the outcomes of the technology”.

Oxford Farming Conference

The Oxford Farming Conference is Britain's leading farming conference, now in its 65th year.

The patrons of the Oxford Farming Conference include lots of respectable names such as the Co-op and the RSPB, but also includes Bayer CropScience, and its sponsors include Syngenta.


The scientist's views, suggesting inappropriate regulation of GMOs, were quoted in Farmers Guardian.  In the midst of a large farming conference at which plenty of interesting initiatives must have been presented, it's interesting to speculate why this particular point got into print.  The statement is suspiciously similar to what seems to have been a PR stunt only two months earlier which erroneously announced to the world that the Vatican supported the advance of GM crops through reduced regulation (see
VATICAN TAKE-OVER BID, ROUND II – January 2011).  Statements like this slipping out all over the place look like an organised attempt to make policy makers feel insecure about their handling of GMOs.  Look out for more PR efforts in the same vein: you may need to reassure your regulators that they are, by no means, over-regulating GM.

There are signs the theory behind the flu-free fowl and observed outcome are not quite as they should be.  The 'blocked' enzyme isn't preventing the virus growing enough to kill the birds, but something inexplicable is preventing H5N1 transmission onwards to cage-mates.  An individual within a flock artificially harbouring a non-contagious but very pathogenic virus could be even more sinister than the disease as it is at present: are we simply creating a chicken soup of viral particles from which a human super-pathogen could most easily emerge. 

To expand on this: so long as the virus can enter chicken cells, there is a risk of recombination with other viral particles.  A virus finding itself unable to replicate easily might be even more encouraged to hijack another virus, use it to bypass all the man-made blocks genetic engineers have installed, and produce something very nasty and uncontrollable indeed.

The tactic of generating RNA blockages in chickens is even more problematic than the insertion of protein-generating genes.  Consider that DNA interacts with itself and with its living milieu: the complexity of these is way beyond our ability to comprehend or predict.  The much smaller and infinitely more varied RNA molecules generated by DNA interact directly with each other, with DNA, with proteins and who knows what else.  This is a level of complexity of life which we destabilise at our peril.

The use of RNA interference, as opposed to an engineered protein makes it particularly important that regulators remain 'obsessed with the technology' because the outcome may be something they didn't bargain for, and YOU will be eating it.

  • Jon Lyall, et al., 2011, Suppression of Avian Influenza Transmission in Genetically Modified Chickens, Science 331 No.6014, 14.01.11
  • Martin Enserink, Transgenic Chickens Could Thwart Bird Flu, Curb Pandemic Risk,
  • Oxford Farming Conference,
  • Cumulative Number of Confirmed Human Cases of Avian Influenza A (H5N1) reported to WHO,, 13.01.11
  • Swan tests confirm deadly virus, BBC News, 6.04.06
  • G birds 'don't spread the flu', Metro 14.01.11
  • William Surman, OFC: Poultry genetically modified to resist avian flu, Farmers Guardian, 6.01.11
  • GM Freeze press release, 13.01.11

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