Free bluetongue testing is being offered for farm livestock in high-risk areas of eastern England in a bid to prevent outbreaks of the potentially-fatal animal disease.

Dozens of infected cattle and sheep were found in Norfolk during the winter, although movement restrictions were eased in February as cold weather limited the activity of virus-carrying midges.

But Defra says the warmer weather means there is currently a "very high probability of a new introduction of bluetongue virus serotype 3 (BTV-3)" this year, through infected biting midges being blown over from northern Europe. 

In the most high-risk coastal counties of Norfolk, Suffolk, Essex, Kent and East Sussex, free testing is being introduced to prevent animal movements potentially transporting undetected diseases to new areas.

Testing is available for animals moving from the highest risk counties to live elsewhere in the country, or to be sold at a market within a high-risk county where there will be buyers from outside the high-risk counties.

Chief veterinary officer Christine Middlemiss said: "Bluetongue does not pose a threat to human health or food safety, but the disease can impact livestock farms, and cause productivity issues. 

"We know that the likelihood of bluetongue virus entering Great Britain is increasing and so I would urge farmers to remain vigilant and report any suspicions to the Animal and Plant Health Agency (APHA). 

"If you intend to move animals to live out of high-risk counties please take advantage of this free testing as it will help stop the movement of undetected disease."

Strict rules on the movement of livestock from regions affected by bluetongue are already in place, and farmers have been warned to monitor their animals frequently for clinical symptoms, and to make sure their animals and land are registered with APHA so animals can be located in the event of an outbreak.

Defra says work is under way with vaccine manufacturers to "facilitate safe access" to a BTV-3 vaccine as soon as possible.

Meanwhile, an "active surveillance programme" is trapping midges across the country and working with partners including the Met Office to monitor the likely spread of the virus based on temperature and wind patterns.  

Bluetongue does not affect human health or food safety, but it is a notifiable disease and livestock keepers must report suspected cases to the APHA on 03000 200 301.