Bird-Flu Stopping Transgenic Chickens Produced

(A. Kotok)

Genetically modified chickens with molecular structures designed to prevent the spread of bird flu have been developed by researchers at the University of Cambridge and Edinburgh University in the U.K. The study is published in this week’s issue of the journal Science (paid subscription required).

The team of scientists successfully developed genetically modified or transgenic chickens that do not transmit to other chickens the avian influenza virus. This new breed of chicken could stop bird flu outbreaks spreading within poultry flocks, with immediate benefits to poultry farmers, and eventually to lower risks of avian flu epidemics in the human population.

To produce these chickens, the scientists introduced a new gene that manufactures a small “decoy” molecule that mimics an important control element of the bird flu virus. The virus’s replication process is tricked into recognizing the decoy molecule instead of the viral genome. This trickery blocks the influenza virus polymerase — the enzyme that catalyzes genetic formation of new viruses — which interrupts replication of the virus.

The transgenic chickens still contracted and became infected with avian flu, but they did not pass on the infection to other chickens kept in the same pens. This happened even if the other chickens were normal (non-transgenic) birds.

One of the paper’s authors, Laurence Tiley at Cambridge, notes that “The decoy mimics an essential part of the flu virus genome that is identical for all strains of influenza A. We expect the decoy to work against all strains of avian influenza and that the virus will find it difficult to evolve to escape the effects of the decoy.”

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