The team found that animals that had the virus inoculated directly into their lungs became severely ill, whereas animals that were infected through the nose or oesophagus did not. All animals infected with the virus still shed infectious virus particles, meaning they could infect other animals.

Following an outbreak of bird flu at a Shropshire farm, the entire county has been put into an Avian Influenza Prevention Zone (AIPZ). This means anyone who has birds in Shropshire must house their animals. This applies whether or not you have just one or two chickens in a back garden right up to large commercial flocks.

British health authorities said on Monday they had detected a case of the H5N1 bird flu in a person in central England but added that the risk to the wider public remained "very low".