www.checkbiotech.org ; www.raupp.info ; www.czu.cz

The long-term threat of an avian flu pandemic could be greatly reduced by a
project to produce genetically modified chickens that can resist lethal
strains of the virus, October 2005 by Mark Henderson, Science Correspondent.

British scientists are genetically engineering chickens to protect them
against the H5N1 virus that has devastated poultry farms in the Far East,
with a view to replacing stocks with birds that are not susceptible to
influenza.

The technique should also offer protection against many other strains of flu
with the potential to start a human pandemic, such as the H7 subgroup that
was responsible for an outbreak in Dutch poultry in 2003.

If chicken populations were to be replaced with transgenic birds that were
resistant to flu, it would remove a reservoir of the virus and make it much
harder for it to spread to humans and trigger a pandemic.

The team, led by Laurence Tiley, Professor of Molecular Virology at
Cambridge University, and Helen Sang, of the Roslin Institute, near
Edinburgh, has already shown that chicken cells can be protected against flu
by inserting small pieces of genetic material.

The researchers are now ready to begin a similar procedure with eggs and the
first experiments are expected within weeks. Any breakthrough, however, will
come too late to have an impact on the present outbreak of H5N1.

Even if the technique works, it will be several years before it can be used
to stock farms and it also faces important regulatory hurdles and a battle
to win over public opinion. If these obstacles are overcome and farmers are
willing to adopt GM chickens, the entire world stock could be replaced
fairly quickly.

?Once we have regulatory approval, we believe it will only take between four
and five years to breed enough chickens to replace the entire world
population,? Professor Tiley said. ?Developing flu-resistant chickens has
clear benefits for human health and animal welfare, as we wouldn?t have to
slaughter chickens around the world. Chickens provide a link between the
wild bird population, where avian influenza thrives, and humans, where new
pandemic strains can emerge. Removing that bridge will dramatically reduce
the risk posed by avian viruses.?

The research team is following three parallel approaches. One involves
inserting a working copy of a gene that makes an antiviral protein called
Mx, which is defective in many chicken breeds, and should improve their
ability to fight off H5N1 and other strains.

The second approach is to harness a technique called RNA interference, in
which small fragments of the genetic signalling chemical RNA are used to
disrupt the workings of the flu virus.

By engineering chicken cells to make small RNA molecules that confuse the
flu virus, the scientists hope to confer resistance to a wide variety of
strains. The third strategy is similar to the second, but involves using RNA
molecules as decoys, which trick the flu virus into copying them rather than
itself. All three could potentially be incorporated in the same GM chickens.

[www.timesonline.co.uk]

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