SHEEP on a farm in North Yorkshire and another in Northumberland have now tested positive for Schmallenberg virus (SBV).

It follows last week’s confirmation of the virus being detected among dairy cattle on a farm in North Yorkshire and another in West Yorkshire.

The findings are the result of tests carried out as part of ongoing Government surveillance measures in parts of the country where there has been no history of the midge-borne virus.

Simon Hall, veterinary director at the Animal Health and Veterinary Laboratories Agency (AHVLA), said the findings indicated the virus had spread to previously unaffected areas during this year’s active midge season.

He said: “When infection occurs in animals that are not pregnant, the impact is very limited and protects against SBV affecting future offspring.

“As we saw in 2012 the overall impact on British farms is relatively limited, although I recognise the concern it causes farmers whose livestock are affected.”

The North-East National Farmers’ Union said the news that SBV had spread to the region was not unexpected.

Richard Potts, regional livestock and dairy adviser, said: “There is no indication that the animals involved had recently been moved from areas of the country where Schmallenberg is more prevalent, so it’s clear these animals were exposed to the disease within the region.

“The big question is when they were infected because with Schmallenberg, timing is everything.

“The real problems associated with the disease – when they affect developing lambs and calves during pregnancy – only occur if the animal is exposed to the disease during a very small window early in the pregnancy.

“Once exposed, the animal then develops immunity, so the ideal scenario is for the disease to spread through an area ahead of the breeding season, leaving immune animals which are then not susceptible.

“At the current time it is not possible to say when these particular animals were infected, but certainly if it was earlier this year then that is potentially good news. That said, it is possible that there could still be infected midges circulating which would be of concern as we are now entering the key breeding season for sheep.

“It is impossible to be precise on this, so giving cast-iron advice to farmers is difficult especially those preparing to put their rams or ‘tups’ out imminently.

“Delaying tupping until later in the year – November/December – when midge activity is at its lowest is not an option for all, but is something some may want to consider in conjunction with their vet.”

Farmers have been urged to remain vigilant for any signs of the disease and report anything unusual to their vet. If Schmallenberg is suspected, a Government-funded test can be requested under the surveillance programme.

NFU members can see a detailed briefing paper on the disease on the NFU website at nfuonline.com.

SBV was first detected in Germany and Holland and reached southern England last year. The most recent results have also detected antibodies in animals on farms in Shropshire, Carmarthenshire and Powys.