English livestock producers are being urged to submit lambs with suspected Schmallenberg virus (SBV) for post-mortem examination as the number of confirmed cases of the disease grows.

The disease was recently detected in lambs on four holdings in the northeast of England, including Northumberland, by the post-mortem diagnostic service at John Warren ABP in Co. Durham.

The Schmallenberg virus was previously detected in the southwest of England last month and subsequently in North Yorkshire.

Schmallenberg is capable of infecting pregnant sheep and cattle and causing severe malformations of foetuses in the womb.

It emerged across western Europe in November 2011. By July 2013, calves, lambs and kids with severe skeletal deformities had been reported in at least 24 European countries.

Importantly, the virus does not spread from animal to animal but, like the Bluetongue virus, is transmitted by midges, which infect the animals when they bite.

No, or very few, cases of Schmallenberg virus causing deformed calves or lambs were confirmed in 2014 or 2015, possibly as a result of immunity built up by animals following the 2011/2012 epidemic.

The possible increase in cases of the disease was predicted in a studied carried out in 2015, Ben Strugnell, of Farm Post Mortem Ltd which operates the service at J Warren ABP, said.

“The possible re-emergence of Schmallenberg was predicted following a study in autumn 2015 which tested young flock replacement sheep in the south of England, the results of which suggested that levels of immunity may have dropped.

“It is very important that, if producers encounter lambs with skeletal deformities, these are submitted for post-mortem examination so that appropriate samples can be taken to establish whether Schmallenberg is the cause.

“The best advice for producers is to contact their vet, who can provide information on the best way to arrange a post-mortem.

Blood sampling of ewes which have affected lambs is useful. Younger sheep may be most at risk, as older ones may be immune from previous exposure to the virus.

“At present there are no vaccines available for Schmallenberg and it is already too late to vaccinate sheep which are due to lamb in spring.

“However, it is important that we ascertain the true levels of the virus, because this will help determine whether there is a need to vaccinate later in the year,” he said.