The government has eased restrictions on Norfolk livestock movements aimed at preventing the spread of bluetongue - as the cold weather has lessened the risk of midges spreading the virus.

On Thursday, Defra identified the potentially-fatal animal disease in three more cattle and one sheep on premises near Surlingham - bringing Norfolk's total to 29 cases since the first infection was found in cattle near Cantley on December 8.

That sparked the creation of a 10km temporary control zone (TCZ) to focus surveillance efforts and enforce restrictions on livestock movements. 

It has caused disruption and uncertainty for livestock farms, as licences were needed to move animals out of the zone, which were only permitted where there is an "urgent and genuine welfare need”, or to go directly to slaughter at a designated abattoir.

Eastern Daily Press: Norfolk's bluetongue temporary control zone (TCZ) was extended on January 27Norfolk's bluetongue temporary control zone (TCZ) was extended on January 27 (Image: Defra)

That zone was extended slightly last weekend after two positive animals were found to have been grazing slightly outside it.

But now Defra says some of the restrictions inside it will be relaxed as the colder weather has reduced the risk of disease transmission from midges.

"Due to a decrease in temperature, we are now in a seasonally vector low period, when midge activity is much lower, and they are not actively feeding," it says.

"Low temperatures also mean that the virus cannot replicate in the midge, so even if a midge does feed on an infected animal, the risk of transmission to another animal is low.

"The reduced risk from midges means that some movements of live animals out of the zone can now be temporarily permitted subject to pre-movement testing and that they meet certain licence conditions. These relaxations will only apply during periods of low vector activity and will not apply to animals that test positive in a pre-movement test.

"During this low vector activity period we will also ease the licence restrictions on movements of animals into and within the TCZs.

"These restrictions will be revised when vector activity increases again with warmer temperatures, which tends to be March or April." 

Because of the reduced risk of transmission, the recently-diagnosed animals will not be culled but will be "restricted at their current locations and disease mitigation measures will be taken", says Defra.

Bluetongue does not affect human health or food safety, but livestock keepers must report suspicions of the virus immediately to the APHA on 03000 200 301.