Government scientists now believe that contaminated poultry meat from Hungary is the most likely source of the outbreak of H5N1 avian flu at the Bernard Matthews turkey farm at Holton, Suffolk.
According to government chief scientist Sir David King, the virus found at Holton is identical to that found on a Hungarian goose farm in January.
Talking to Radio Five Live on Friday, he said this effectively ruled out the possibility that the virus was transported to East Anglia by a contaminated wild bird.
“I would conclude that this is a poultry-to-poultry infection, not a wild bird-to-poultry infection.
“If it was wild bird-to-poultry, there would have been some transformation in the virus by the time it got here,” he said.
Investigations were still ongoing, but Sir David said his guess was that semi-processed poultry meat had arrived at the processing factory, alongside the turkey houses.
The good meat would have been processed for the human food chain and the waste product set-aside for disposal.
He suggested that some other vector, possibly rats, may have carried the infected waste material into a turkey shed. “This is one possibility,” he said.
“It would be a matter of concern if it has got into the wild population, as this then raises the question as to whether we have contained it.”
It has now been revealed that H5N1 has been detected in three of the 22 turkey sheds at Holton, not one as previously reported.
Earlier in the week Bernard Matthews had insisted there was no contact between its UK and its Hungarian operations. But it has now emerged that there was a regular trade in turkey meat between the two countries.
Commercial director Bart Dalla Mura told the BBC that the company did transport meat, but not live birds.
He insisted he would be “very surprised” if Hungarian turkey meat was the source of infection.
“There is no suggestion of any infection at our Hungarian plant and no suggestion of any infection in turkeys in Hungary,” he said.
The two previous avian flu outbreaks in Hungary were on goose farms almost 200 miles away from the Bernard Matthews plant.
But as a precautionary measure, the company has suspended movements to and from Hungary.
Liberal Democrat agriculture spokesman Chris Huhne said there appeared to have been serious biosecurity lapses on the part of Bernard Matthews and called for penalties if investigations led to any convictions.
For more information, see our Special Report on avian flu.