New tool in battle against avian flu

A UK researcher has developed a new method of protecting birds against avian flu, that has been shown to be effective against a range of strains, including H5N1 and the H7N2 strain in the current outbreak in Lancashire.

As Nigel Dimmock at the University of Warwick explains, existing vaccination methods depend on stimulating the body’s immune system, so that white blood cells produce antibodies that attach to the surface of the virus and start the process of killing it.

One drawback is that the coat of the flu virus is continually changing, so vaccination against one strain of flu, for instance H3N2, is totally ineffective against another, such as H5N1.

However, Prof Dimmock’s new approach developed over the last 20 years overcomes this by using an entirely new method, that uses a ‘protecting virus’. This virus contains genetic material that has been altered, rendering the virus harmless and unable to spread like a normal flu virus.

If it is joined in the cell by another influenza virus, it starts to reproduce at a much faster rate than the new influenza virus. This fast reproduction rate – spurred by the new flu infection – means that the new invading influenza is effectively crowded out by the ‘protecting virus’.

Prof Dimmock explains that this slows the progress of the new infection, prevents flu symptoms and gives the body time to develop an immune response to the harmful new invader.

“In effect the protecting virus converts the virulent virus into a harmless live vaccine.”

Trials show that this virus gives the samebeneficial effect for all strains.

“This is particularly valuable as a preventative measure as you don’t need to know the exact make up of the new strain before deploying the protecting virus

In addition it protects instantly, whereas protection generated by conventional flu vaccination takes 2-3 weeks to become fully effective.

He sees the ‘protecting virus’ having a useful role in poultry, as it is possible to deliver it in the bird’s drinking water. One dose should protect a chicken for weeks.

The Warwick research team has now filed a patent for the ‘protecting virus’ and are looking to carry out further trials.