Farmers are preparing for their industry to be thrown into chaos as Somerset last night confirmed its first case of the potentially lethal bluetongue virus.

An outbreak of the deadly disease, which causes mouth ulcers, fever and can kill livestock, has been confirmed on a cattle farm in Yeovil.

The Department of Food and Rural Affairs (Defra) said one cow, which was imported from France, had tested positive for the virus in the past 24 hours.

The announcement comes two days after bluetongue was also confirmed in imported cattle at a farm near Dorchester, Dorset.

Dairy farmer and NFU representative Michael Oakes, said: "I think this latest case shows the need for farmers to be vigilant, to vaccinate and to think carefully when importing.

"When bringing cattle over, it is so important to be careful as the disease is rampant in some areas of the EU."

The NFU advised farmers to support its JAB campaign, which aims to get all cattle and sheep vaccinated against the bluetongue, which is caused by a virus spread by certain types of biting midges.

The bluetongue outbreak comes at the end of a worrying week for Somerset farmers.

Ian Ham, who runs Alston Sutton Farm in Weare, near Axbridge, will have to destroy the infected cattle in his dairy herd and temporarily close his farm after tests showed the animals had contracted bovine tuberculosis.

NFU South West spokesman Ian Johnson said that TB was at the root of many of the agricultural industries problems and has compounded the bluetongue problem as farmers had to import cattle they could no longer buy in Britain.

He said: "Farmers are having to import cattle because it's so hard to get heifers here as a result of TB.

"Although cattle are vaccinated and tested on the continent, it makes the risk of bluetongue significantly higher and that's what we are seeing."

Wells MP David Heathcoat-Amory and MP for Weston-super-Mare John Penrose have been in crisis talks with Mr Ham, other local farmers and National Farmers' Union representatives to discuss how to prevent the disease from spreading to other farms in the Cheddar Valley and across Somerset.

They believe the most effective course of action would be a controlled cull of badgers which the farming community is convinced spread the disease which has catastrophic consequences for West agriculture.

Mr Johnson said: "Scientific research has proved the badgers spread the disease and yet they still roam the fields completely unfettered.

"To try to protect the cattle from infection through any other means than a cull is almost impossible; it's like spitting into a hurricane.

"Thousands of cattle are being slaughtered and although there is a compensation scheme in place for farmers, it is not representative of what many of the animals are worth and doesn't take into account pedigree breeds which are worth considerably more.

"If a herd is infected, the farm has to close for an undisclosed period of time. I know of one case where the farm was closed for two years.

"These losses are not taken into account, there is no compensation for any other losses."

Figures from the Department of Environment Food and Rural Affairs show about 50,000 cattle have been slaughtered this year as a result of bovine TB, almost double 2007's total of 28,000.

It is estimated that more than 100 herds in Somerset have contracted the disease between January and May this year.