Bluetongue protection zone set up

The case is near Poole, and the new protection zone covers the whole of Dorset and the New Forest, Defra said.

As a result of the case, which was identified during routine pre-movement testing, the wider surveillance zone which covers much of England has also been extended into south east Wales as well as all of Somerset and Devon.

Three new cases in Sussex, Essex and Norfolk have also been identified, which means the separate protection zones covering East Anglia and parts of north west London, Buckinghamshire and Hertfordshire have been merged and extended.

A Defra spokeswoman said all the infected animals were found as a result of the testing that farmers must undertake before they are able to move their livestock out of the zones.

The disease, which can be fatal to animals such as sheep and cows, is spread by midges.

In December the Government announced "a vector-free period" in which risk of the virus spreading was considered low because of a lack of midge activity in the cold weather.

The evidence suggests the animals all had the disease before the vector-free period began, making it unlikely the virus is currently circulating in the UK, Defra said. It is not yet clear how the disease reached the infected site near Poole.

The Defra spokeswoman said further similar cases may be expected in the coming weeks. A case of the disease was identified last week in Greater London.

The Environment Department is hoping to have a vaccine for the strain of bluetongue currently affecting animals in Europe available by early summer when the disease is expected to re-emerge.