A countywide restriction on the movement of farm animals has been brought in after a rise in cases of an infectious disease which is spreading across wildlife.

UK chief veterinary officer Christine Middlemiss set out further measures to tackle bluetongue following 70 confirmed cases across the UK.

The viral disease can cause infertility and breathing problems in cattle, sheep, goats and deer but does not pose a threat to humans or food.

It was found in five cows at two premises in Canterbury in November in the first cases countrywide before spreading to the Sandwich Bay area where a further three cows tested positive in December.

A temporary control zone (TCZ) which stretched from Canterbury to Thanet and down to Dover, was set up in order to stop the spread of the virus.

A new, larger restricted area will now cover the whole county and parts of neighbouring East Sussex.

The rules mean susceptible animals cannot be moved out of the zone without a specific licence while keepers in the area will need to follow strict guidelines on animal movements.

Farmers have been reminded that animals imported from these regions must be accompanied by the relevant paperwork to clearly show they meet certain conditions designed to reduce disease risk, such as correct vaccination.

Animal and plant health agency chief executive Jenny Stewart said: "Since the first BTV-3 case for this season was detected last month, case numbers have continued to rise.

“I want to remind keepers of the importance of monitoring their livestock and taking up free testing where necessary."

In a bid to tackle the crisis, the government has also confirmed it will permit the use of unauthorised bluetongue vaccines.

The Department for Environment, Food & Rural Affairs (Defra) said movements within a zone will be allowed and a general licence to move animals to designated abattoirs was available – keeping the food chain moving.

The virus is spread by midges that are often blown over from mainland Europe during spells of warm weather.